AHU Applications Application Note - Johnson Controls

Issue Date January 31, 2006

© 2006 Johnson Controls, Inc. www.johnsoncontrols.com Code No. LIT-6375080

APPLICATION NOTE

AHU Applications

Using AHU Applications .......................................................................3

Introduction......................................................................................................... 3

Key Concepts...................................................................................................... 4

AHU Applications ..............................................................................................................4 Mixed Air Single Path Applications ...................................................................................5 100% Outside Air Single Path Applications ....................................................................18 Mixed Air Dual Path or 100% Outside Air Dual Path Applications .................................. 20 Heat Recovery for 100% Outside Air Applications..........................................................25 Economizer .....................................................................................................................27 Preheat............................................................................................................................ 31 Heating............................................................................................................................ 37 Cooling ............................................................................................................................ 42 Dehumidification..............................................................................................................47 Humidification.................................................................................................................. 49 Modes of Operation.........................................................................................................51 Fan System .....................................................................................................................58 Using an AHU Application in a UNT Controller ...............................................................62

Procedure Overview......................................................................................... 64

Detailed Procedures......................................................................................... 65

Creating a Mixed Air Single Path Application..................................................................65 Creating a 100% Outside Air Single Path Application..................................................... 68 Creating a Mixed Air Dual Path or 100% Outside Air Dual Path Application .................. 69 Completing the Heat Recovery for 100% Outside Air Question/Answer Path ................ 70 Completing the Economizer Question/Answer Path .......................................................72 Completing the Minimum Duct Requirements Question/Answer Path ............................ 75 Completing the Vent and Purge Question/Answer Path .................................................79

AHU Applications Application Note 2

Completing the Preheat Question/Answer Path..............................................................81 Completing the Heating Question/Answer Path..............................................................89 Completing the Cooling Question/Answer Path ..............................................................98 Completing the Dehumidification Question/Answer Path..............................................106 Completing the Humidification Question/Answer Path..................................................109 Completing the Modes of Operation Question/Answer Path.........................................111 Completing the Fan System Control Question/Answer Path......................................... 117

Troubleshooting ............................................................................................. 125

Downloading an AHU Application ................................................................................. 125 Saving an AHU Application File for a UNT Controller ................................................... 126

Point Assignments and Parameters ............................................................. 127

Default Point Assignments ............................................................................................127 Default Parameters ......................................................................................................*131


Using AHU Applications

Introduction The AHU (Air Handling Unit) application is capable of controlling many different air handlers and control strategies. This application note introduces AHU applications and provides procedures for configuring these applications using the question/answer path. This application note describes how to:

• create a mixed air single path application

• create a 100% outside air single path application

• create a mixed air dual path or 100% outside air dual path application

• complete the heat recovery for 100% outside air question/answer path

• complete the economizer question/answer path

• complete the minimum duct requirements question/answer path

• complete the vent and purge question/answer path

• complete the preheat question/answer path

• complete the heating question/answer path

• complete the cooling question/answer path

• complete the dehumidification question/answer path

• complete the humidification question/answer path

• complete the modes of operation question/answer path

• complete the fan system control question/answer path


Key Concepts AHU Applications

The AHU application is capable of controlling many different air handlers and control strategies (Figure 1). The types of air handling applications that can be controlled include:

• Mixed Air Single Path

• Mixed Air Dual Path

• 100% Outside Air Single Path

• 100% Outside Air Dual Path

Air Handlers100% Outside Air

Dual Path

FLWCHT3

New

File

Air HandlersMixed Air

Single Path

Air HandlersMixed Air Dual Path

Air Handlers100% Outside Air

Single Path

Open

Select Existing File Name

Figure 1: AHU Application Path Each of these applications are explained in the following topics. Use the Table of Contents at the beginning of this document to locate the application you are using. Every question is listed for the entire AHU application, along with explanations for each answer. The AHU controller can be downloaded as a generic point multiplexer. The unused points can be user defined and used with up to 16 sideloops.


Mixed Air Single Path Applications

Schematic Figure 2 is a schematic of a mixed air single path application.

AirflowStatusExhaust

N.C.

Mixed Air Dampers N.O.

N.C.Outside

Note:Coil arrangement may differ:- Preheat coil may be in the outside air duct before the mixed air sensor.- Heating coil may be after the cooling coil for dehumidification control.- Heating and/or cooling coil may be after the supply fan.

Mixed AirTemperature

PreheatTemperature

PreheatCoil

HeatingCoil

CoolingCoil Supply

Fan

ReturnFan

AirflowStatus

AirflowStation

AirflowStation

Humidifier

Return

Discharge

StaticPressureDischarge

AirTemperature

MASPDUCT

Return Air Temperature and

Humidity

Figure 2: Mixed Air Single Path Schematic

Control Strategy The first question in the mixed air single path question/answer path (Figure 50) asks you to select the control strategy. The available strategies are:

• Room Control

• Room Control of Cooling, Room Reset of Heating

• Supply Air Reset from Zone Temperature (Mixed Air)

• Return Air Control

• Constant Discharge Air Temperature

• Supply Air Reset from Return Temerature The following provides information on each of the six available strategies.


Room Control The Room Control strategy uses the zone temperature to directly control each controlled device (Figure 3). As the zone temperature decreases into the heating proportional band, the system commands the preheat (if selected and sequenced) and heating devices in sequence. As the zone temperature increases above the zone cooling setpoint, the system controls the outdoor air damper (if selected and sequenced) and mechanical cooling device in sequence. As the zone temperature travels through the various proportional bands, the output to the associated controlled device ranges from 0 to 100%. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.


MA

SPR

AC

.cdr

Occupied

MaximumSelect

Logic

Multiply

0 - 1

EconomizerCommand

Return SetpointHeating DeadbandHeating Proportional BandPreheat Proportional BandHeating IntegrationEconomizer Proportional BandCooling DeadbandCooling Proportional BandCooling IntegrationReturn Air Temperature

Heating Command

Preheat Command

Cooling Command

Economizer Command

Go ToEconomizerSwitchover

Logic

Economizer

0

SupplyAirflow Shutdown

0

HeatingIntegration

Term

0

SupplyAirflow

Shutdown

0

CoolingIntegration

Term

0

Separate Mixed Air Closed Loop

100%

02 1

1 Mixed Air SetpointMixed Air Prop Band2

Mixed Air Integration TermMixed Air Deadband

Mixed Air Temperature

Economizer Command

Mixed Air Low Limit

1

02

1

12

Mixed Air Low Limit Setpoint

Mixed Air Low Limit Proportional Band


Mixed Air Low LimitDeadbandMixed Air Low LimitIntegration Term


0

Mixed AirLow Limit

IntegrationTerm

0

Single PI

Return Control Sequencer

PHTGHTG

ECONCLG

3

2

14

1234

5

6

7567

Mixed AirLow Limit

Offset

MinimumPosition*

*See

the

section for more information.

Is Minimum Damper Position Reset from an Air Quality Sensor Needed?

Figure 3: Room Control


Room Control of Cooling, Room Reset of Heating This control strategy uses the zone temperature to reset a discharge air heating setpoint and directly control the cooling device (Figure 4). As the zone temperature increases above the zone cooling setpoint, the system controls the outdoor air damper (if selected and sequenced) and mechanical cooling device in sequence. As the zone temperature travels through the proportional band, the output to the associated controlled device ranges from 0 to 100%. The controller calculates a discharge heating setpoint based on the input heating reset schedule. The discharge heating low limit establishes a calculated discharge setpoint when the zone temperature first enters the zone heating proportional band. The system adds the discharge heating reset band to this low limit. This value is the number of degrees the discharge setpoint changes as the zone temperature decreases through the zone heating proportional band. The discharge sensor then controls and sequences the preheat (if selected and sequenced) and heating device as the discharge temperature decreases below the calculated discharge setpoint. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control. The heating device will remain active when cooling is locked out based on the outside air temperature. This maintains a discharge heating low limit even when the zone temperature is in the cooling proportional band.


SupplyAirflow

Shutdown

0

HeatingIntegration

Term

0

SupplyAirflow

Shutdown

0

CoolingIntegration

Term

0

MAS

PR

CR

R.c

dr

Economizer Command

Heating SetpointDischarge Htg Prop BandDischarge Htg IntegrationDischarge Preheat Prop BandDischarge Sensor

Economizer LogicOccupied

Mixed Air LowLimit Offset

Occupied

0 - 1

Heating Control 100%

0

0

ECON

Sequencer

CLGHTGReset

Zone SetpointHeating DeadbandHeating Proportional BandHeating IntegrationDischarge Heating Low LimitDischarge Heating Reset BandEconomizer Proportional BandCooling DeadbandCooling Proportional BandCooling IntegrationZone Temperature

0

Heating Command

Preheat Command

Multiply MaximumSelect

1

4

3 2

5

6

7

Discharge Heating SetpointCooling CommandEconomizer Command


100%

02 1



Mixed Air TemperatureEconomizer Command

1

02

1

12

Mixed Air Low Limit Setpoint

Mixed Air Low Limit Proportional Band




0

Mixed AirLow Limit

IntegrationTerm

0

Single PI

8

123

45 678

Mixed AirLow Limit


Logic

MinimumPosition*

*See

the section

for more information.


Figure 4: Room Control of Cooling, Room Reset of Heating


Supply Air Reset from Zone Temperature (Mixed Air) The supply air reset from zone temperature strategy resets the discharge air setpoint for heating and cooling (Figure 5). The zone proportional band is divided by two and each half is active above and below the zone setpoint. As the zone temperature varies away from the zone setpoint within the zone proportional band, it calculates the actual discharge setpoint based on a discharge low limit and discharge reset band. This strategy uses a discharge sensor to control heating and cooling around the actual discharge setpoint. It controls and sequences the preheat (if selected and sequenced) and heating devices as the discharge temperature decreases below the actual discharge setpoint minus the heating deadband. The discharge sensor also controls the outside air damper (if selected and sequenced) and mechanical cooling device as the discharge air temperature increases above the actual discharge setpoint plus the cooling deadband. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.


HTGPHTG ECON

CLG

2

MA

SPA

RZT

.cdr

Discharge SetpointHeating DeadbandHeating Integration TimeHeating Proportional BandPreheat Proportional BandEconomizer Proportional BandCooling DeadbandCooling Integration TimeCooling Proportional BandDischarge Temperature


Logic

Preheat CommandHeating CommandCooling CommandEconomizer Command

Occupied

MaximumSelect

Multiply

0 - 1

EconomizerCommand

0

43

5 6

7

1

0

12

2

1

1

2

21

1 Zone Setpoint

Zone Integration Time

Discharge Low Limit

Discharge Reset Band

Reset BandZone PI

0-100%

Zone Temperature

2


100%

0 2 1




Economizer Command

2

1 Mixed Air Low Limit SetpointMixed Air Low Limit Proportional Band



DischargeSetpoint

0% 100%

Single PI

1

12

345 6

7

SupplyAirflow

Shutdown

0

HeatingIntegration

Term

0

SupplyAirflow

Shutdown

0

CoolingIntegration

Term

0

SupplyAirflow

Shutdown

0

Mixed AirLow Limit

IntegrationTerm

0


0

Mixed AirLow Limit

IntegrationTerm

0

2 Zone Proportional Band 2

EconomizerLogic

Mixed AirLow Limit

Offset

Discharge Temperature Loop

Mixed Air Low Limit

MinimumPosition*

*See

the section



Figure 5: Supply Air Reset from Zone Temperature


Return Air Control The return air control strategy uses the return air temperature to directly control each controlled device (Figure 6). This strategy commands the preheat (if selected and sequenced) and heating devices in sequence as the return air temperature decreases below the return setpoint minus a heating deadband. As the return temperature increases above the return air setpoint, the return air control strategy controls the outdoor air damper (if selected and sequenced) and mechanical cooling devices in sequence. As the return air temperature varies through the heating and cooling proportional bands, the output to the controlled device ranges between 0 to 100%. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.


MASPRAC

Occupied

MaximumSelect

Logic

Multiply

0 - 1

EconomizerCommand

Return SetpointHeating DeadbandHeating Proportional BandPreheat Proportional BandHeating IntegrationEconomizer Proportional BandCooling DeadbandCooling Proportional BandCooling IntegrationReturn Air Temperature

Heating Command

Preheat Command

Cooling Command

Economizer Command

MinimumPosition


Logic

Economizer

0


0

HeatingIntegration

Term

0

SupplyAirflow

Shutdown

0

CoolingIntegration

Term

0


100%

02 1




Economizer Command

Mixed Air Low Limit

1

02

1

12

Mixed Air Low Limit SetpointMixed Air Low Limit Proportional Band




0

Mixed AirLow Limit

IntegrationTerm

0

Single PI

Return Control Sequencer

PHTGHTG

ECONCLG

3

2

14

1234

5

6

7567

Mixed AirLow Limit

Offset

Figure 6: Return Air Control


Constant Discharge Air Temperature The constant discharge air temperature strategy uses the discharge air temperature to directly control each controlled device (Figure 7). It commands, in sequence, the preheat (if selected and sequenced) and heating device as the discharge air temperature decreases into the heating proportional band. As the discharge temperature increases above the discharge air setpoint, the system controls the outdoor air damper (if selected and sequenced) and mechanical cooling devices in sequence. As the discharge temperature varies through heating and cooling proportional bands, the output to the controlled device ranges between 0 to 100%. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.


MA

SPC

DC

.cdr

Occupied

MaximumSelectMultiply

0 - 1Command


Economizer LogicSee Economizer Switchover Logic

0

Preheat Command

Heating Command

Cooling Command

Economizer Command

Mixed AirLow Limit

Offset


Logic

Economizer

SupplyAirflow

Shutdown

0

HeatingIntegration

Term

0

SupplyAirflow

Shutdown

0

CoolingIntegration

Term

0


100%

0 2 1

1 Mixed Air Setpoint orDischarge Air SetpointMixed Air Prop Band2


Mixed Air Temperature Economizer Command

Mixed Air Low Limit

1

02

1

12

Mixed Air Low Limit SetpointMixed Air Low Limit Proportional Band



SupplyAirflow

Shutdown

0Mixed AirLow LimitIntegration

Term

0

User-Selected Setpoint for Mixed Air Control


0

Mixed AirLow Limit

IntegrationTerm

0

Single PI

3

21

456

7

Discharge Control Sequencer

PHTGHTG

ECONCLG

32

14 5

76

MinimumPosition*

*See

the

section for more information.


Figure 7: Constant Discharge Air Control


Supply Air Reset from Return Temperature The supply air reset from return temperature strategy resets the discharge air setpoint for heating and cooling (Figure 8). As the return temperature varies below the return high limit and within the return reset band, it calculates a discharge setpoint based on a discharge low limit and discharge reset band. The return proportional band is divided and active above and below the return setpoint. The discharge low limit establishes the discharge setpoint when the return temperature is at the warmest end of the return proportional band. The value of the discharge reset band is the number of degrees added to the discharge low limit as the return temperature decreases through the return proportional band. This strategy uses a discharge sensor to control heating and cooling around the calculated discharge setpoint. It controls and sequences the preheat (if selected and sequenced) and heating devices as the discharge temperature decreases below the calculated discharge setpoint minus the heating deadband. The discharge sensor also controls the outside air damper (if selected and sequenced) and mechanical cooling device as the discharge air temperature increases above the calculated discharge setpoint. As discharge temperature varies through the heating and cooling proportional bands, the outputs to the controlled devices modulate between 0 to 100%. Integration may be added to these control loops to eliminate the inherent offset associated with proportional only control. Economizer Command may include resetting the minimum position see Figure 8, based on indoor air quality. See the Is Minimum Damper Position Reset from an Air Quality Sensor Needed? section for more information.


HTGPHTG ECON

CLG

2

MASPSART


Discharge Temperature Loop


Logic

Preheat Command

Heating Command

Cooling Command

Economizer Command

Occupied

MaximumSelectMultiply

0 - 1

EconomizerCommand

MinimumPosition*

0

43 5 6

7

Mixed Air Low Limit

1

0

12

Return High LimitReturn Reset BandDischarge Low LimitDischarge Reset BandReturn Air Temperature

Reset Band


100%

0 2 1



Mixed Air TemperatureEconomizer Command

2

1 Mixed Air Low Limit SetpointMixed Air Low Limit Proportional Band

Mixed Air SensorMA-T


1

SupplyAirflow

Shutdown

0

HeatingIntegration

Term

0

SupplyAirflow

Shutdown

0

CoolingIntegration

Term

0

SupplyAirflow

Shutdown

0

Mixed AirLow Limit

IntegrationTerm

0

2

345 6

7 1

EconomizerLogic

Mixed AirLow Limit

Offset

*See

the section



Figure 8: Supply Air Reset from Return Temperature


100% Outside Air Single Path Applications

Schematic Figure 9 is a schematic of a 100% outside air single path application.

AirflowStatus

Exhaust

N.C.

Outside

Note:Coil arrangement may differ:- Heating coil may be after the cooling coil for dehumidification control.- Heating and/or cooling coil may be after the supply fan.

PreheatTemperature

PreheatCoil

HeatingCoil

CoolingCoil Supply

Fan

ExhaustFan

AirflowStatus

AirflowStation

AirflowStation

Humidifier

Return

Discharge

StaticPressureDischarge

Air Temperature

OASPDUCT

Exhaust AirTemperature

andHumidity

N.C.

Figure 9: 100% Outside Air Single Path Schematic

Question/Answer Path The questions and answers for 100% Outside Air Single Path (OASP) are identical to those for Mixed Air Single Path (MASP), with a few exceptions:

• 100% OASP provides exhaust air temperature control, instead of return air control as in MASP.

• Supply air reset from exhaust temperature is not available for 100% OA units, as supply air reset from return temperature was available for MASP units.

• The supply air reset from zone temperature is unique for 100% OA.

• There is no economizer section for 100% OA control, so when finished with this section, see the Heat Recovery for 100% Outside Air Applications section.


Supply Air Reset from Zone Temperature (100% OA Single Path) The supply air reset from zone temperature strategy resets the discharge air setpoint for heating and cooling (Figure 10). As the zone temperature rises into the zone cooling proportional band, it calculates a discharge setpoint based on a discharge cooling low limit and discharge cooling reset band. When the zone temperature drops below the zone setpoint, minus the zone heating deadband and into the zone heating proportional band, a discharge setpoint is calculated based on a discharge heating low limit and discharge heating reset band. This strategy uses a discharge sensor to control heating and cooling around the calculated discharge setpoint. It controls and sequences the preheat (if selected and sequenced) and heating devices as the discharge temperature decreases below the actual discharge setpoint minus the discharge heating deadband. The discharge sensor also controls the mechanical cooling device as the discharge air temperature increases above the actual discharge setpoint. As discharge temperature varies through the heating and cooling proportional bands, the output to the controlled devices modulate between 0 to 100%. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.

8

SPSARZT2

Zone SetpointHeating DeadbandHeating Proportional BandDischarge Heating Low LimitDischarge Heating Reset BandHeating IntegrationCooling Proportional BandDischarge Cooling Low LimitDischarge Cooling Reset BandCooling Integration

Discharge Setpoint

Heating DeadbandHeating Proportional BandPreheat Proportional BandCooling Proportional BandCooling Integration

Discharge LoopPreheat Command

Heating Command

Cooling Command

Zone Loop

1

4

3

2

5

67

1

432

5

6 78

9 10 11 12

10

12 11

9

Figure 10: Supply Air Reset from Zone Temperature


Mixed Air Dual Path or 100% Outside Air Dual Path Applications

Schematic Figure 11 is a schematic of a dual path application.

SupplyFan

CoolingCoil

HeatingCoil

Hot DeckTemperature

Cold DeckTemperature

N.O.

Supply Air

Zone Control(by separate controller)

N.C.

MADPDUCT

* From PreheatCoil Discharge

* See 100% Outside Air Single Path or Mixed Air Single Path schematic for return/exhaust fan, dampers, and preheat coil.

Figure 11: Dual Path Schematic

Control Strategy The first question in the mixed air dual path or 100% outside air dual path question/answer path (Figures 52 and 53) asks you to select the control strategy. The available strategies are:

• Multizone Hot/Cold Deck Reset

• Dual Duct Hot/Cold Deck Reset

• Multizone Zone Control

• Dual Duct Zone Control The following provides information on each of the four available strategies.

Multizone Hot/Cold Deck Reset or Dual Duct Hot/Cold Deck Reset This control strategy controls typical multizone or dual duct type air handlers (Figure 12). It uses the temperature from the warmest and coldest zone, and calculates a cold deck and hot deck setpoint through a cold and hot deck reset schedule respectively. The cold deck setpoint and the cold deck discharge temperature controls the outdoor air damper (if sequenced with cooling) and mechanical cooling device in sequence. The hot deck setpoint and the hot deck temperature control the heating device. When a preheat device is selected, it will be controlled as a Separate Mixed Air Closed Loop. It is recommended that the preheat setpoint be a value lower than the cold deck low limit.


DPRHCDR2

Hot Deck ControlColdest Zone High LimitColdest Zone Reset BandHot Deck Low LimitHot Deck Reset BandColdest Zone Temperature

Hot Deck Setpoint

Heating Proportional BandHeating Integration

HotDeck

Cold Deck Setpoint

Cooling Proportional BandCooling Integration

Cold Deck Control

Coldest Zone

Warmest ZoneWarmest Zone High LimitWarmest Zone Reset BandCold Deck Low LimitCold Deck Reset BandWarmest Zone Temperature

5

1

32

4

5

12

4

3

5 6

6

1

32

41

3

2

4

5

6

6

Heating Command

CoolingCommand

Figure 12: Multizone Hot/Cold Deck Reset or Dual Duct Hot/Cold Deck Reset

Reset Schedule The four input parameters of each reset schedule determine the reset schedule for the cold and hot deck. The hot zone high limit, hot zone reset band, cold deck low limit, and cold deck reset band establish the cold deck reset schedule. The system uses the warmest zone temperature to calculate the cold deck setpoint through this reset schedule. The cold zone high limit, cold zone reset band, hot deck low limit and hot deck reset band establish the hot deck reset schedule. The system uses the coldest zone temperature to calculate the hot deck setpoint through this reset schedule. The coolest and warmest zone temperatures are individual analog inputs. Zones that are not the warmest or coolest control their zone damper through separate control loops outside of this sequence.

Cold Deck Control If the system is mixed air dual path, the outdoor air damper and mechanical cooling device are in sequence. As the cold deck temperature rises above the calculated cold deck setpoint and enters the economizer proportional band, the economizer dampers will modulate from minimum position to 100% open (if economizer is enabled). The cold deck cooling deadband is added to the cold deck setpoint and establishes the cold deck temperature value at which the mechanical cooling proportional band begins. An alternate cooling deadband is used when Econ mode is not available. As the cold deck temperature rises through the cold deck proportional band, the mechanical cooling device will modulate from 0 to 100% open. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.


The system controls the outdoor air dampers from minimum position during the Occupied mode and from 0% during the Unoccupied mode. It is possible to eliminate the operation of the outdoor air damper in Unoccupied mode by setting the unoccupied economizer proportional band equal to zero.

Hot Deck Control The system controls the hot deck heating device when the hot deck temperature is below the calculated hot deck setpoint. As the temperature enters the heating proportional band, the output to the controlled device will modulate from 0 to 100% open. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control. Zone Mixing Damper Control For satisfying the load in the space, the system requires zones that are not the warmest or coldest to mix the hot and cold deck air streams. This means that a separate closed loop must exist outside the AHU controller to control each of the zone dampers. Individual zone temperature control may be a pneumatic loop with a T-4002 thermostat controlling the zone damper. The system brings the multiple thermostats into a C-2220 high/low signal selector that selects the zones with the greatest heating and cooling demands. The system brings these signals out of the C-2220 and into two FM-IAP101-0s. The FM-IAP101-0s convert the high and low pneumatic signals into 4 to 20 mA signals that connect into the AHU controller. HVAC PRO can scale this signal internally to the sensitivity range of the T-4002 thermostat.* * Refer to the Appendix D: Multizone Hot and Cold Deck Reset

Application Note in the Appendix section of the HVAC PRO User’s Manual, which explains how to set up the analog inputs for the warmest and coolest zones.

Typically, on digitally controlled zones, a supervisory system like Metasys® Companion/Facilitator or Metasys Network Control Module (NCM) is applied to select the warmest and coolest zones from the zone controllers, and then globally share this data with the AHU.


Multizone Zone Control or Dual Duct Zone Control This control strategy takes the warmest and coldest zone inputs and directly controls the cold and hot deck respectively (Figure 13). It is appropriate for direct zone control of dual duct and multizone systems.

DPMRZC2

Coldest Zone Temperature (CZ-T)Zone Heating SetpointHeating Proportional BandHeating IntegrationWarmest Zone Temperature (WZ-T)Zone Cooling SetpointCooling Proportional BandCooling Integration

Hot Deck Command

Cold Deck Command

Zone LoopCLGHTG

34

12

2 1 3 4

CZ-T WZ-T

Figure 13: Zone Control

Warmest Zone Control The system controls the outdoor air damper (if selected and sequenced) and mechanical cooling device in sequence. As the warmest zone temperature rises above the calculated warmest zone setpoint and enters the economizer proportional band, the economizer dampers will modulate from minimum position to 100% open (if Econ is enabled). The warmest zone cooling deadband is added to the warmest zone setpoint and establishes the warmest zone temperature value at which the mechanical cooling proportional band begins. An alternate cooling deadband is used when Econ mode is not available. As the warmest zone temperature rises through the warmest zone proportional band, the mechanical cooling device will modulate from 0 to 100% open. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control. The system controls the outdoor air dampers from minimum position during the Occupied mode and from 0% during the Unoccupied mode. It is possible to eliminate the operation of the outdoor air damper by setting the unoccupied economizer proportional band equal to zero.

Coolest Zone Control The system controls the heating device below the calculated coolest zone setpoint. As the coolest zone temperature decreases below the calculated coolest zone setpoint and enters the heating proportional band, the output to the controlled device will modulate from 0 to 100% open. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.


Zone Mixing Damper Control For satisfying the load in the space, the system requires zones that are not the warmest or coldest to mix the hot and cold deck air streams. This means that a separate closed loop must exist outside the AHU controller to control each of the zone dampers. Individual zone temperature control may be a pneumatic loop with a T-4002 thermostat controlling the zone damper. The system brings the multiple thermostats into a C-2220 high/low signal selector that selects the warmest and coldest zones. The system brings the warmest and coldest zone signals out of the C-2220 and into two FM-IAP101-0s. The FM-IAP101-0s convert the high and low pneumatic signals into 4 to 20 mA signals that connect into the AHU controller. HVAC PRO scales this signal internally to the sensitivity range of the T-4002 thermostat.* * Refer to the Appendix D: Multizone Hot and Cold Deck Reset

Application Note in the Appendix section of the HVAC PRO User’s Manual, which explains how to set up the analog inputs for the warmest and coolest zones.

Typically, on digitally controlled zones, a supervisory system like Metasys Companion/Facilitator or Metasys NCM is applied to select the warmest and coolest zones from the zone controllers, and then “globally share” this data with the AHU.


Heat Recovery for 100% Outside Air Applications

Heat Recovery Type The first question in the heat recovery for 100% outside air applications question/answer path (Figure 54) asks you to select the heat recovery type. The available types are:

• 2-position Output from Analog Input Sensor

• Run Around Glycol Loop The following provides information on each of the available types.

2-Position Output from Analog Input Sensor When the outdoor or discharge air temperature (user selectable via question) decreases below the heat recovery setpoint, a maintained binary output energizes, causing the 2-position heat recovery device (Figure 14) to be on or open. When the temperature increases to a value that is equal to the heat recovery setpoint plus the heat recovery differential, the controller commands the heat recovery device off or closed. If the heat recovery control sensor becomes unreliable, the command to the heat recovery device is off or closed. This control loop must have proven airflow. Whenever the system loses airflow or when the Shutdown mode is on, the system commands the heat recovery device off or closed.

HR2PDifferential

Outdoor Air or Discharge Air Temperature

Heat Recovery Setpoint

NOT

Shutdown

Airflow

00

OR

Compare FailSoft

BOHeat Recovery

Figure 14: Heat Recovery for 2-Position Device

Run Around Glycol Loop When the heat recovery temperature decreases below the heat recovery setpoint and into the heat recovery proportional band, the 3-way valve opens to allow modulated flow between the exhaust and supply coils (Figure 15).


HR-GL

BO

PI Control

Multiply

Shutdown Airflow

Heat Recovery AO

1.0%Differential 1.0%

Glycol Low Limit

Heat Recovery SetpointProportional Band

IntegrationOffset

DeadbandHeat Recovery AI

0

0

Glycol Low Limit SetpointProportional Band

IntegrationDeadband

Glycol Temperature

Pump Start

ComparePI

12

12

0 - 1

1 2

0

1

12

Figure 15: Run Around Glycol Loop Whenever the glycol temperature decreases below the glycol low limit setpoint, the low limit loop backs off the heat recovery loop causing more flow to the exhaust coil to protect the exhaust coil from condensation and frost. The Shutdown mode or loss of airflow commands the output to the heat recovery valve to 0% open. See Figure 16.

Return

Discharge

Exhaust

Glycol TemperaturePump

Heat RecoveryValve

HeatRecovery

Temperature

Outside N.C.

GLYCOL

N.C.

Figure 16: Heat Recovery Device


Economizer

Description The system controls the outdoor air dampers from minimum position during the Occupied mode and from 0% during the Unoccupied mode. Through the unoccupied control parameters, you can eliminate outdoor air damper operation during the Unoccupied mode.

ELCAMAS

100%

Vent Airflow Shutdown

100%

Economizer Command

Outdoor Air TemperatureFailSoft

Purge

0

0 Economizer Command AOMinimum Position, 0, or

Last Command

Figure 17: Economizer Logic Common to All Systems

Switchover Strategy The last question in the economizer question/answer path (Figure 55) asks you to select the switchover strategy. The available strategies are:

• None

• Software (N2) Command

• Hardware BI Point

• Dry Bulb

• Enthalpy Comparison

• Outdoor Air Enthalpy

• Fixed Temperature Differential The following provides information on each of the available strategies.

None When you do not select an economizer strategy, the outdoor air damper modulates from minimum position to 100% open to provide cooling without switchover logic intervention. Unless “free cooling” from outside air is available year around, this selection is usually not valid (that is, the outdoor air dampers will open to provide cooling even when the outdoor air has a high heat content).


Software (N2) Command A binary data point is generated for a Facility Management System (FMS) to command (Figure 18). One controller can determine economizer changeover logic and report it to the FMS which can then distribute the information to the other controllers on the network through their binary data points. When economizer is commanded on, free cooling is available.

ELN2C

N2 Command(ECON)

Minimum Position

Control Command From Sequencer

ECON

Figure 18: Software (N2) Command

Hardware BI Point A binary input is used to read the output from an outdoor air temperature switch (Figure 19). When the switch closes (BI is On), the economizer status is off; when the switch opens (BI is Off), the economizer status is on. When economizer status is on, free cooling is available.

EBI

NOTBIECON

ECON

Figure 19: Hardware BI Point

Dry Bulb The outdoor air temperature is compared to an economizer switchover setpoint to determine economizer status (Figure 20). The economizer status is off when the outdoor air temperature exceeds the switchover setpoint. When the outdoor air temperature is less than the switchover setpoint minus a two degree differential, economizer status is on. If the outdoor air sensor is unreliable, economizer status is off. When economizer status is on, free cooling is available.

EDBS

Switchover DifferentialECON

Outdoor Air Temperature CompareSwitchover Setpoint

Figure 20: Dry Bulb Switchover


Enthalpy Comparison Return air temperature and humidity are used to calculate the return air enthalpy (Figure 21). Outdoor air temperature and humidity are used for calculating outdoor air enthalpy which is then compared to the return air enthalpy. When the outdoor air enthalpy exceeds the return air enthalpy, or the outdoor air temperature exceeds the dry bulb default, economizer status is off. When the outdoor air enthalpy is less than the return air enthalpy minus the enthalpy differential switchover and the outdoor air temperature is less than the dry bulb default minus a two degree differential, economizer status is on. If either the return temperature or return humidity becomes unreliable, the outdoor air enthalpy is compared to a failsoft enthalpy of 30 Btu/lb. If the outdoor air humidity sensor becomes unreliable, the outdoor air temperature is compared to the default economizer setpoint. If the outdoor air temperature sensor becomes unreliable, the economizer status is off. When the economizer status is on, free cooling is available.

EC

Outdoor Air Temperature

Outdoor Air RH

EnthalpyCalculation

Outdoor Air Temperature Compare

NOTORCompare

12

1 2ECON

EnthalpyDifferential

Economizer SwitchoverDry Bulb Setpoint

(Default)

EnthalpyCalculation

Return Air Temperature

Return Air RH

Figure 21: Enthalpy Comparison


Outdoor Air Enthalpy Outdoor air temperature and humidity are used to calculate outdoor air enthalpy for comparison to an enthalpy switchover setpoint (Figure 22). If the outdoor air enthalpy exceeds the enthalpy switchover setpoint, or if the outdoor air temperature exceeds the default economizer setpoint, economizer status is off. When the outdoor air enthalpy is below the enthalpy switchover setpoint minus a differential of one Btu/lb, and if the outdoor air temperature is below the default economizer setpoint default minus a two degree differential, the economizer status is on. If the humidity sensor is unreliable, then the controller uses only the default economizer setpoint to determine economizer status. If the outdoor air sensor becomes unreliable, the economizer status is off. When economizer status is on, free cooling is available.

EOAES

Differential


Outdoor Air RH

EnthalpyCalculation

Outdoor Enthalpy Setpoint

Outdoor Air TemperatureEconomizer Switchover

Dry Bulb Setpoint

Compare

NOTORCompare

12

1 2ECON

Figure 22: Outdoor Air Enthalpy

Fixed Temperature Differential The outdoor air temperature is subtracted from the return air temperature and compared to the temperature differential switchover (Figure 23). Economizer status is off when the difference between the temperatures is less than the temperature differential switchover. When the difference between the temperatures exceeds the temperature differential switchover plus a two degree differential, the economizer status is on. If either the outdoor air or return air sensors becomes unreliable, economizer status will be off. When economizer status is on, free cooling is available.

EFTD

Return Temperature

Outdoor Temperature

Subtract

Economizer Switchover Differential

SetpointDifferential = 2.0

Compare NOT ECON

Figure 23: Fixed Temperature Differential


Preheat

Device Type The first question in the preheat question/answer path (Figure 61) asks you to select the preheat device type. The available types are:

• 2 Position Steam/Water Valve (Sensor Cntl’d)

• Face and Bypass w/Vlv Switch over Seq w/Htg Clg

• Modulated Single Coil

• Staged The following provides information on each of the available types.

2 Position Steam/Water Valve (Sensor Cntl’d) When the outdoor, mixed, or discharge temperature (user selected) falls below the preheat low limit setpoint, the controller commands a binary output to on (Figure 24). When the temperature rises above the preheat low limit setpoint plus the preheat low limit differential, the controller commands the binary output to off. Airflow interlock is optional in this control loop.


PC2PV

Airflow Interlock (BI)or

Remain in Control (1)

(Preheat Lockout)

0%100%

Purge

Vent

NOTBOPreheat

Shutdown

Differential

AND

Compare


Loss of Airflow Choice0% = 0

100% = 1Remain in Control = 1

0, 1

0

NOT

AND

Compare

FailSoft

AND

AND

NOT

OR

AND OR

AIPreheat Low Limit

Setpoint Differential

Figure 24: 2-Position Steam/Water Valve

Face and Bypass w/Vlv Switch over Seq w/Htg Clg This control strategy is part of the main control strategy selected at the beginning of HVAC PRO (Figure 25). The discharge air or zone temperature controls this loop depending on your selection. When the outdoor air temperature is below the outdoor air face and bypass switchover setpoint, the controller commands the preheat valve to 100% open, while it modulates the face and bypass damper. As the control temperature falls through the preheat proportional band, the damper shall modulate from bypass (0%) to face (100%). When the outdoor air temperature rises above the outdoor air face and bypass switchover setpoint plus the outdoor temperature face/bypass differential setpoint, the controller commands the face damper to 100% face and modulates the preheat valve to obtain the control setpoint.


PCFB

.cdr

100%

Pump Start

100%

Vent Airflow

Shutdown

BO

Airflow Shutdown

FailSoft

AO Preheat Valve

CompareOutdoor TemperatureFace and Bypass

Switch Setpoint

Preheat Command

FailSoft

Purge

0

OutdoorTemperature

0

(Lockout)

Compare

AO Face and Bypass

Compare00

SetpointOutdoor Temperature

Differential

0, 100, orRemain in

Control

0, 100, orRemain in

Control

0, 100, orRemain in

Control

0, 100, orRemain in

Control

0, 100, orLast Reliable

Command


Command

Figure 25: Face and Bypass with Valve Switchover


The preheat proportional band allows the sequence of preheat operation as the control temperature decreases below the control setpoint. A heating device can be sequenced and controlled as the control temperature continues to decrease below the preheat band. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control. The integration term for this control loop is shared with the sequenced heating device. This option is not valid for Dual Path units.

Modulated Single Coil This strategy allows the preheat device to be controlled as an independent loop or as part of the main control strategy (Figure 26). The preheat proportional band allows the sequence of preheat operation as the control temperature decreases below the control setpoint. A heating device can be sequenced and controlled as the control temperature continues to decrease below the preheat proportional band. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control. The integration term for this control loop is shared with the sequenced heating device.

PMSC2

PI

Outdoor TemperatureSetpoint

Differential

Purge Vent Airflow

Shutdown

AOPreheat

BOPump

Preheat SetpointProportional Band

IntegrationOffset

Deadband

Mixed Air Temperature (Rev 1.0)Separate Sensor (Rev 2.0)

or

Preheat Command

FailSoft


Command

0

0

0

0

00

Compare

Compare

12

12

Figure 26: Modulated Single Coil


Staged This strategy allows electric preheat stages to be controlled as an independent loop or as part of the main control strategy (Figure 27). The preheat stages energize as the control temperature decreases into the preheat proportional band. It can be sequenced with a preheat device if selected. Adding integration to a control loop with staged outputs is not advised, as it usually results in the constant cycling of the outputs. Staged outputs are airflow interlocked. The integration for this loop is shared with the sequenced heating device.

PS2

Preheat SetpointProportional Band

IntegrationOffset

Deadband

Mixed Air Temperature (Rev 1.0)Separate Sensor (Rev 2.0)

Purge

Outdoor Temperature

Lockout Setpoint

Differential

Vent

Compare

Airflow

Preheat Command

or

Shutdown

0, 100, orRemain in

Control

00

0 0

FailSoft

BOSequencer

Timers

1234

12

1

2

>

Figure 27: Staged

Sequencer - Number of Stages The minimum on/off and interstage on/off timers can be adjusted once for all stages or for each individual stage. Once it is on, the minimum on timer keeps a stage energized for a minimum time period. Once it is off, the minimum off timer does not allow a stage to be re-energized for a minimum time period. The interstage delay on and off timers prevent the next stage from energizing or de-energizing until the interstage timer has expired. The interstage on timer for Stage 1 controls the elapsed time before Stage 2 may be turned on. The interstage timer for Stage 2 must elapse before Stage 3 may be turned on, and so on. The reverse is true for the interstage off timers. The interstage on of the last stage has no effect, and the interstage off of the first stage has no effect.


Use the cycles per hour adjustment to restrict the unit from over cycling by providing a minimum time between starts. The cycle per hour feature divides a one hour period into equal cycle intervals. A value of six divides a one hour period into six, 10-minute intervals. Once a stage is commanded on, ten minutes must elapse before another on command is issued. Once a stage is turned off, it cannot be turned on again until the cycle per hour interval and minimum off timer are satisfied. The starting point of the first stage can be adjusted to any value that is 5% or greater and less than the starting point of the second stage. The command and starting point of each stage is based on the 0 to 100% command into the sequencer, with the proportional division of the number of stages over a 0 to 100% range. When you select the first stage to start at 0%, the starting point of the first stage defaults to the normal proportional division (that is, 3 stages would start at 33, 67, and 100% commands). You can override the preheat stages by commanding the pseudo-analog output for preheat. This ensures a 0 to 100% override value is used, keeping the timers inside the sequencing logic active. Individual binary outputs are not eligible to be overridden when part of a sequencer.

IMPORTANT: Staged outputs remain on for their defined minimum on time, regardless of their commanded state.

When all stages must be turned off without delay, adjust the interstage off time to 0. The minimum on timer can hold a stage on even though the Shutdown mode or airflow interlock is active. Keep minimum on timers at the smallest possible value or 0. AHU controllers with C06 firmware or later and UNT (Unitary) controllers with B00 firmware or later will utilize an Instant Off feature. This feature will force all staged outputs off on loss of airflow or shutdown regardless of timer conditions.


Heating

Device Type The first question in the heating question/answer path (Figure 64) asks you to select the heating device type. The available types are:


• Modulated Common Htg and Clg Coil

• Staged

• 2-Position Valve w/Face and Bypass

• Position Adjust - Incremental The following provides information on each of the available types.

Modulated Single Coil The system controls the modulated single heating coil through the main control sequence of operation (Figure 28). The controller sequences the operation of the heating coil with preheat (if selected and sequenced) and cooling. The heating valve will modulate as the control temperature decreases below the control setpoint and into the heating proportional band. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.

ABO1A

SoftHeating

Command

Purge Vent Airflow Shutdown

AO

Pump Start

BO0

0

0

00, 100, or

Last Reliable Command

0

Compare

Heating LockoutSee Lockout illustration. (Figure 29)

Fail

Figure 28: Modulated Single Coil Heating


HeatingLockout

N2 Command

Outdoor Air TemperatureHeating Lockout Setpoint

Differential

Compare

HeatingLockout


Differential

Compare

N2 Command withAI Backup

AI Switch

N2 Command Status

N2 Command

HeatingLockout

CommandLOCKOUT

Figure 29: Lockout

Modulated Common Htg and Clg Coil The common heating and cooling coil is controlled through the main sequence of operation (Figure 30). During the Winter mode of operation (sum/win = on), the controller shall modulate the valve from fully closed to open as the control temperature decreases below the control setpoint and passes through the heating proportional band (Figure 31). The heating signal shall be sequenced with preheat (if selected and sequenced). During the Summer mode of operation (sum/win = off), the controller shall modulate the valve from fully closed to open as the control temperature increases above the control setpoint and passes through the cooling proportional band. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.


ABO2

SoftHeating Command


AOCooling

Command

AISetpoint

Differential

BO

orSUM / WIN(N2 or BI)

0

0

0

0

00, 100, or


Pump Start

Compare

CompareHeating and Cooling Lockout

See Lockout illustrations.(Figures 29 and 35)

Fail

Figure 30: Modulated Common Heating and Cooling Coil

HeatingHigh SetpointDifferential

Heating/Cooling Sensor

Winter Mode

Summer ModeAHUSUMWI

Figure 31: Summer/Winter Switchover

Staged This strategy allows electric heating stages to be controlled as part of the main control strategy (Figure 32). The heating stages energize as the control temperature decreases into the heating proportional band. It can be sequenced with a preheat device if selected. Adding integration to a control loop with staged outputs is not advised, as it usually results in the constant cycling of the outputs.


ABO3

Airflow ShutdownVentPurge

0

0

0

0

0

BOFace and Bypass

Compare

Heating Command

0, 100, orLast Reliable Command

BOSequencer

Timers

1234

AOVernier Control


FailSoft

Figure 32: Staged Heating

2-Position Valve w/Face and Bypass The heating command from the main control sequence modulates a face and bypass damper as the control temperature decreases into the heating proportional band (Figure 33). A 2-position command will open a heating valve when the heating command increases above a user adjustable setpoint. This output has adjustable minimum on and off timers. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.

ABO3A

FailSoft

Airflow ShutdownVentPurge

Heating Command

0

0

0

0

00, 100, or


Compare

AOFace and Bypass

BOValve


Figure 33: 2-Position Valve with Face and Bypass

Position Adjust – Incremental The controller uses two binary outputs to position the control valve. The stroke time you specify determines the timing of these binary outputs. The controller uses the zone temperature to determine the required position of the valve. Then it energizes the appropriate output for a percent of full stroke to achieve the required valve position.


As the zone temperature drops below the heating setpoint, the controller energizes the appropriate output to open the valve. As the zone temperature increases, the controller energizes the other output to close the valve. When the temperature is within the deadband of the controller, neither output is energized and the valve stays in its current position. As the required position drops below the current position, the controller energizes the appropriate output to close the valve. As the required position increases, the controller energizes the other output to open the valve. When the change from the current position to the calculated new position is within the controller’s deadband, neither output is energized, leaving the valve in its current position. The controller uses overdrive logic to ensure the position of the valve. When the output reaches 99%, it will be driven for 1.5 times the stroke time, causing the valve to reach its 100% position.

Sequencer - Number of Stages You can adjust the minimum on/off and interstage on/off timers once for all stages or for each individual stage. Once it is turned on, the minimum on timer keeps a stage energized for the input time period. The minimum off timer does not allow a stage to be re-energized for a time period once it is turned off. The interstage delay on and off timers prevent the next stage from energizing or de-energizing until the interstage timer has expired. The interstage on timer for Stage 1 controls the elapsed time before Stage 2 may be turned on. The interstage timer for Stage 2 must elapse before Stage 3 may be turned on, and so on. The reverse is true for the interstage off timers. The interstage on of the last stage has no effect, and the interstage off of the first stage has no effect. Use the cycles per hour adjustment to restrict the unit from over cycling by providing a minimum time between starts. The cycle per hour feature divides a one hour period into equal cycle intervals. A value of six divides a one hour period into six 10-minute intervals. Once a stage is turned on, ten minutes must elapse before another on command is issued. Once a stage is turned off, it cannot be turned on again until the cycle per hour interval and minimum off timer is satisfied.


The starting point of the first stage can be adjusted to any value that is 5% or greater and less than the starting point of the second stage. When you answer this question 0%, the stages are automatically proportioned over the heating proportional band. The command and starting point of each stage is based on the 0 to 100% command into the sequencer, with the proportional division of the number of stages over a 0 to 100% range. When you select the first stage to start at 0%, the starting point of the first stage defaults to the normal proportional division (i.e., 3 stages would start at 33, 67, and 100% commands). You can override the heating stages by commanding the pseudo-analog output for heating. This ensures a 0 to 100% override value is used, keeping the timers inside the sequencing logic active. Individual binary outputs are not eligible to be overridden when part of a sequencer.


When all stages must be turned off without delay, adjust the interstage off time to 0. The minimum on timer can hold a stage on even though the Shutdown mode or airflow interlock is active. Keep minimum on timers at the smallest possible value or 0. AHU controllers with C06 firmware or later and UNT controllers with B00 firmware or later will utilize an Instant Off feature. This feature will force all staged outputs off on loss of airflow or shutdown regardless of timer conditions.

Cooling

Device Type The first question in the cooling question/answer path (Figure 68) asks you to select the cooling device type. The available types are:


• Staged

• 2-Position Valve w/Face and Bypass

• Position Adjust - Incremental The following provides information on each of the available types.


Modulated Single Coil The system controls the modulated single cooling coil through the main control sequence (Figure 34). The controller sequences operation of the cooling coil with heating and outdoor air damper operation (if sequenced). As the control temperature increases above the zone or discharge setpoint, through the cooling deadband and into the cooling proportional band, the controller issues a 0 to 100% command to the cooling device. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.

ABO4A

Vent Airflow Shutdown

AO

DehumidificationLogic

CoolingCommand

00

0

0

0

FailSoft

BOPump Start

0, 100, or Last Reliable Command

Compare

See the

section.

Cooling LockoutSee Lockout illustration. (Figure 35)

Purge

Dehumidification

Figure 34: Modulated Single Coil Cooling

CoolingLockout

N2 Command

Outdoor Air TemperatureCooling Lockout Setpoint

Differential

Compare

CoolingLockout


Differential

Compare


AI Switch

N2 Command Status

N2 Command

CoolingLockout

Command

CLGLOCK

Figure 35: Lockout


Staged This strategy allows Direct Expansion (DX) cooling stages to be controlled as part of the main control strategy (Figure 36). The controller sequences the DX stages as the control temperature increases into the cooling proportional band. Adding integration to a control loop with staged outputs is not advised as it usually results in the constant cycling of the outputs.

ABO4B

FailSoft



CoolingCommand

0 0 0

0

0, 100, orRemain in Control

BOSequencer

Timers

1234

AOVernier Control


See theDehumidification

section.

Figure 36: Staged Cooling

2-Position Valve w/Face and Bypass The cooling command from the main control sequence modulates a face and bypass damper as the control temperature increases into the cooling proportional band. A 2-position command will open a cooling valve when the cooling command increases above a user adjustable setpoint. This output has adjustable minimum on and off timers. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.

Position Adjust – Incremental The controller uses two binary outputs to position the control valve. The timing of these outputs is based on an operator specified stroke time. The controller uses the zone temperature to determine the required position of the valve. Then the controller will cause the appropriate output to energize for a percent of full stroke to achieve the required valve position. As the zone temperature rises above the cooling setpoint, the controller energizes the appropriate output to open the valve. As the zone temperature decreases, the controller energizes the other output to close the valve. When the temperature is within the deadband of the controller neither output energizes, leaving the valve in its current position. The controller uses overdrive logic to ensure the position of the valve. When the output reaches 99%, it will be driven for 1.5 times the stroke time, causing the valve to reach its 100% position.


Sequencer - Number of Stages The minimum on/off and interstage on/off timers can be adjusted once for all stages or for each individual stage. Once turned on, the minimum on timer keeps a stage energized for the input time period. Once turned off, the minimum off timer does not allow a stage to re-energize for the input time period. The interstage delay on and off timers prevent the next stage from energizing or de-energizing until the interstage timer has expired. The interstage on timer for Stage 1 controls the elapsed time before Stage 2 may be turned on. The interstage timer for Stage 2 must elapse before Stage 3 may be turned on, and so on. The reverse is true for the interstage off timers. The interstage on of the last stage has no effect, and the interstage off of the first stage has no effect. Use the cycles per hour adjustment to restrict the unit from over cycling by providing a minimum time between starts. The cycle per hour feature divides a one hour period into equal cycle intervals. A value of six divides a one hour period into six 10-minute intervals. Once a stage is turned on, ten minutes must elapse before another on command can be issued. Once a stage is turned off, it cannot be turned on again until the cycle per hour interval and minimum off timer is satisfied.

ABO4C

FailSoft



CoolingCommand

AOFace and Bypass

0 0

0

00, 100, or


0BO

Cooling Valve

Compare


See theDehumidification

section.

Figure 37: Rotational Sequencing of Cooling


The starting point of the first stage can be adjusted to any value that is 5% or greater and less than the starting point of the second stage. The command and starting point of each stage is based on the 0 to 100% command into the sequencer, with the proportional division of the number of stages over a 0 to 100% range. When you select the first stage to start at 0%, the starting point of the first stage defaults to the normal proportional division (that is, 3 stages would start at 33, 67, and 100% commands). You can override the DX stages by commanding the pseudo-analog output for cooling. This ensures a 0 to 100% override value is used, keeping the timers inside the sequencing logic active. Individual binary outputs are not eligible to be overridden when part of a sequencer.




Dehumidification

Control Strategy The first question in the dehumidification question/answer path (Figure 70) asks you to select the control strategy. The available strategies are:

• High Signal Selection w/Cooling Command

• Addition of Dehumid. and Cooling Command The following provides information on each of the available strategies.

High Signal Selection w/Cooling Command This control strategy selects the highest signal between the sensible cooling command and the dehumidification command, then outputs the selected value to the cooling device (Figure 38). The cooling command originates from the main temperature control sequence of operation. When the relative humidity increases above the humidity setpoint and into the dehumidification proportional band, a dehumidification command is determined. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.

ABO5

SoftMaximum

Select

Dehumidification SetpointProportional Band

IntegrationDeadband

Humidity AIOffset

0

Integration

Airflow

PI 0

Go ToCoolingLogic

1 orOccupied

1 2 0 orLast Command

12

CoolingCommand

Fail

Figure 38: High Signal Selection with Cooling Command

Addition of Dehumidification and Cooling Command This control strategy adds the sensible cooling command from the main sequence of operation to the dehumidification command and outputs the total value to the cooling device (Figure 39). The cooling command originates from the main temperature control sequence of operation. When the relative humidity increases above the humidity setpoint and into the dehumidification proportional band, a dehumidification command is determined. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.


ABO5A

FailSoft

Dehumidification SetpointProportional Band

IntegrationDeadband

Humidity AIOffset

Integration

Airflow

Go ToCoolingLogic

100.0

PI

ADDMinimum

Select

0

0

1 orOccupied

12

21 0 orLast Command

CoolingCommand

Figure 39: Addition of Dehumidification and Cooling Command


Humidification

Description A humidity high limit device is recommended with any humidification strategy. The device should be located in the supply duct, at least eight feet downstream of the humidifier. A device such as the HLC-1000 can be used to limit the electronic signal to the humidifier from the controllers analog output when a high limit setpoint is reached.

Sequencer - Number of Stages The minimum on/off and interstage on/off timers can be adjusted once for all stages or for each individual stage. Once turned on, the minimum on timer keeps a stage energized for the input time period. Once turned off, the minimum off timer does not allow a stage to re-energize for the input time period. The interstage delay on and off timers prevent the next stage from energizing or de-energizing until the interstage timer has expired. The interstage on timer for Stage 1 controls the elapsed time before Stage 2 may be turned on. The interstage timer for Stage 2 must elapse before Stage 3 may be turned on, and so on. The reverse is true for the interstage off timers. The interstage on of the last stage has no effect, and the interstage off of the first stage has no effect. Use the cycles per hour adjustment to restrict the unit from over cycling by providing a minimum time between starts. The cycle per hour feature divides a one hour period into equal cycle intervals. A value of six divides a one hour period into six 10-minute intervals. Once a stage is turned on, ten minutes must elapse before another on command can be issued. Once a stage is turned off, it cannot be turned on again until the cycle per hour interval and minimum off timer is satisfied. The command and starting point of each stage is based on the 0 to 100% command into the sequencer, with the proportional division of the number of stages over a 0 to 100% range (i.e., 3 stages would start at 33, 67, and 100% commands). You can override the humidity stages by commanding the pseudo-analog output for humidity. This ensures a 0 to 100% override value is used, keeping the timers inside the sequencing logic active. Individual binary outputs are not eligible to be overridden when part of a sequencer.





Modes of Operation

Unoccupied Control Strategy Note: When occupied is on, the controller assumes the occupied

setpoints and operates as normal.

The first question in the modes of operation question/answer path (Figure 73) asks you to select the control strategy. The available strategies are:

• Intermittent Night Operation from Zone Sensor

• Setup/Setback of Htg/Clg Setpts in Main Seq Operation from Zone (Only in Room Control Strategy)

The following provides information on each of the available strategies.

Intermittent Night Operation from Zone Sensor The intermittent night operation selection is a valid option for all the AHU control strategies including:

• Room Control

• Return Air Control

• Constant Discharge Air Control

• Supply Air Reset from Return/Exhaust

• Room Control of Cooling/Room Reset of Heating

• Supply Air Reset from Zone This selection requires a zone sensor which will only be used for night operation. When the controller is in the Unoccupied mode and the zone temperature is above the night cooling or below the night heating setpoint, the unit will start (Figure 40).


BO9

XOROccupied

Warmup/Cooldown

Two Minutes

15 Seconds

BOSupply Fan

Zone TemperatureNight Heating

SetpointDifferential

Zone TemperatureNight Cooling


Shutdown

Supply Air Flow

NOT AND AND

OR OR

DelayOn

DelayOff

AND

NOT

OR

Compare

Compare

Figure 40: Intermittent Night Operation: Supply Fan Start The system controls the control temperature around the occupied heating and cooling setpoints. When the constant discharge air control strategy is selected, user adjustable unoccupied discharge heating and cooling setpoints are used. When the system commands the fan on due to zone temperature, the appropriate discharge temperature is delivered to the zone. The controller commands the fan system off when the zone temperature increases above the night heating setpoint plus the night heating differential, or below the night cooling setpoint minus the night cooling differential. If the mixed air dampers are sequenced with cooling, you may want to prevent free cooling in the Unoccupied mode by setting the unoccupied economizer proportional band to 0. When the economizer status is not on, the mechanical cooling algorithm operates with the alternate cooling deadband (default = 0). This moves the starting point of mechanical cooling to the control setpoint.


BO9A

Shutdown BOSupply Fan

Zone TemperatureNight Heating


Zone TemperatureNight Cooling


XOR

Return Air Flow15 Seconds

BOReturn FanFan

Delay

Occupied

Warmup/Cooldown

NOT

OR OR

AND

Supply Air Flow15 Seconds

Fan Delay Between

FansAND

DelayOff

DelayOff

DelayOn

AND

AND

NOT

DelayOn

AND

OR

Compare

Compare

Figure 41: Intermittent Night Operation: Supply and Return Fan Start

Setup/Setback of Htg/Clg Setpts in Main Seq Operation from Zone (Only in Room Control Strategy) The setup and setback option is only available when the main control strategy is room control. The controller adds the setup value to the zone cooling setpoint and subtracts the setback value from the zone or heating setpoint. The controller does not use the heating deadband when calculating the setback value. The setback value replaces the heating deadband. The unit fans will start when the preheat (if selected and sequenced), heating, economizer (if selected and sequenced) or cooling proportional command reaches 10% and the unit will stop when the commands have decreased to 1%. Once the unit fan starts and airflow status is on, the command is passed through to the appropriate heating or cooling device. It is likely that once the unit starts in the Setup/Setback mode, it will continue to run for the rest of the unoccupied period while maintaining the setup or setback setpoint. See Figures 42 through 44.


ABO7

ADD

Warmup/Cooldown

Warmup/Cooldown

Occupied

ZoneSetpoint

Occupied

Go toMain Control Strategy

(Zone Setpoint)

Setup

Setback

0 0

ADD

Go toMain Control Strategy(Heating Deadband)

HeatingDeadband

Figure 42: Setup and Setback: Setpoint Logic

ABO7A

Zone Heating Command 10%

Shutdown

Occupied

NOT

Zone Economizer Command 10%

Zone Preheat Command 10%

Airflow15 Seconds

Zone Cooling Command 10%

DelayOn

DelayOff

2 Minutes

BOSupply Fan

XOR

Compare

Compare

Compare

Compare

OR

OR

OR

OR

AND

NOT AND

AND

Figure 43: Setup and Setback: Single Supply Fan


BO8

Supply Air Flow

15 Seconds

15 Seconds

Return Air Flow

XOR

Shutdown

Occupied

Fan DelayBetween Fans

2 Minutes

Fan DelayBO

Return Fan

ADD

DelayOn

DelayOff

DelayOff

DelayOn

BOSupply Fan

Same Logic asSingle Supply Fan

Logic

NOT

OR

AND

AND AND

NOT AND

Figure 44: Setup and Setback: Supply and Return Fan Logic

If the mixed air dampers are sequenced with cooling, you may want to prevent free cooling in the Unoccupied mode by setting the unoccupied economizer proportional band to 0. When the economizer status is not on, the mechanical cooling algorithm operates with the alternate cooling deadband (default = 0). This moves the starting point of mechanical cooling to the control setpoint value plus the setup value.

Shutdown Mode The default of the Shutdown mode (Figure 45) is off. When shutdown is enabled, all outputs to fans are turned off, outside air dampers are closed, and the humidity devices are shutdown. Preheat, heating, and cooling outputs will be shutdown to 0% command if the user specified they be affected by shutdown. Otherwise, they will go to their loss of airflow position. In Shutdown mode, all integration timers are set to 0, so no windup occurs when the system is put back into control.


B010A

N2 Command StatusZone Bus Communication Status

Default Shutdown Start

Default Shutdown Stop

N2 ShutdownCommand

ShutdownCommand

TimeSchedule

Start/Stop

OR

Figure 45: Shutdown Mode

Warmup/Cooldown Mode The Warmup/Cooldown mode is only available if an unoccupied strategy is selected and may only operate in the Unoccupied mode. When commanded on, the Warmup/Cooldown mode stops the unoccupied temperature control strategy selected and starts the fan system if it is not running. It then controls to the temperature setpoints selected for occupied operation. On mixed air systems, if free cooling is available, the mixed air dampers shall modulate from 0 to 100% open, ignoring the minimum outside air position. As the control temperature approaches the control setpoint, the system modulates or stages the controlled devices (preheat, heating, cooling). When the controller switches into Occupied mode, warmup/cooldown ends. This allows the minimum outdoor air dampers to open. Even though Warmup mode ends, it remains on until commanded off. When the Occupied mode is turned off, but the warmup/cooldown is left on, Warmup/Cooldown mode will operate until commanded off. If you selected the constant discharge air control strategy, an unoccupied discharge air setpoint is used until the zone temperature achieves the warmup/cooldown zone setpoint. If the zone temperature is below the warmup/cooldown zone setpoint, the unoccupied heating discharge air setpoint shall be used. If the zone temperature is above the warmup/cooldown zone setpoint, the unoccupied cooling discharge air setpoint shall be used. Once the zone temperature reaches the warmup/cooldown zone setpoint, the discharge air will control to the (occupied) discharge air setpoint. The warmup/cooldown zone differential is used to prevent switching back to the unoccupied discharge air setpoints once the warmup/cooldown zone setpoint is achieved.


Airflow Interlock and Alarm An airflow switch is incorporated into the controller operation. A two minute delay is in effect after a command to start the fan is sent, allowing time to prove airflow. Airflow must be proven in order to operate the economizer output. If loss of airflow is detected for more than 15 seconds, the preheat, heating, and cooling outputs will be commanded to the user selected loss of airflow output and a fan alarm indication will be given. If you select a return fan, return airflow must be proven for normal operation. In the Fan System Control section, a Fan Commanded Off Upon Loss of Air Flow question is asked. If you answer no, a loss of airflow will not shut down the fan system. Once airflow is in alarm, the airflow status must toggle from off to on to clear the alarm.

Default Schedule When you initiate Occupied mode and shutdown through the software (N2) command only, you can input a default occupied and shutdown start/stop time schedule. This schedule is in effect whenever the N2 Bus is offline longer than ten minutes. The time clock that operates inside the AHU controller is not battery backed. It resets to 00:00 whenever you apply power to the controller or the controller goes through a reset condition, such as when downloaded.

B010

N2 Command StatusZone Bus Communication Status

Default Occupied Start

Default Occupied Stop

OccupiedCommand

TimeSchedule

Start/Stop

OR

N2 OccupiedCommand

Figure 46: Default Schedule The only way to set the controller’s time clock to any time other than 00:00 is through the NCM or Companion/Facilitator via the N2 Bus, or a Zone Terminal (ZT) configured with a weekly schedule for that controller. Whenever you connect a laptop to the Zone Bus (but not a ZT), the controller enters the Service mode. The Service mode disconnects the AHU controller from the N2 Bus. The Occupied mode can be overridden from the Commissioning program of HVAC PRO when you connect the laptop to the Zone Bus (or N2 Bus).


Fan System

Control Type The first question in the fan system control question/answer path (Figure 75) asks you to select the fan system control type. The available types are:

• Single Supply Fan with Static Press. Cntl.

• Single Sup/Ret Vol Match w/Static Pres Cntl

• Single Supply, Low/High Speed Control

• Constant Volume The following provides information on each of the available types.

Single Supply Fan with Static Press. Cntl. Supply fan output is the trigger for static pressure control. Supply fan status enables the integration term. If the ramp control is not used, the proportional output must be sufficient to make the fan status. This control strategy allows the control of variable frequency/speed drives, inlet vanes or discharge dampers that control static pressure within the air handling system. The static pressure setpoint is in inches of Water Gauge (WG) or Pascals for metric units. The static pressure proportional band, integration value, and derivative weight determine the gain of the control loop. An integration value is always recommended to eliminate the proportional offset in this control loop, as precise static pressure control is required in most cases. Usually derivative control action is not necessary, and the derivative weight should be input as 0. The system adds the static pressure offset value to the PID control calculation and usually remains at 0. The static pressure deadband value establishes a range above and below the static pressure setpoint where the error is considered 0. The deadband is applied above and below the static pressure setpoint. If the static sensor becomes unreliable, the command to the static pressure control device equals 0%.


NORAMP

AOSupply FanControl

000

Static Pressure

StaticIntegrationTerm

FailSoft

0

MINSelect

Static Pressure 1Static Pressure 2

Supply Fan Cmd

XORANDDelayON

Supply FanCommand

DelayOFF

SupplyAirflow

Process VariableSetpoint

Proportional BandIntegrationDerivative

OffsetDeadband

Figure 47: Single Supply Fan, Static Pressure, without Ramp Control

Single Sup/Ret Vol Match w/Static Pres Cntl Supply fan output is the trigger for static pressure control. Supply fan status enables the integration term. If the ramp control is not used, the proportional output must be sufficient to make the fan status. This control strategy allows the control of variable frequency/speed drives, inlet vane or discharge dampers that control static pressure within the air handling system. The static pressure setpoint is in inches of Water Gauge (WG) or Pascals for metric units. The static pressure proportional band, integration value, and derivative weight determine the gain of the control loop. An integration value is always recommended to eliminate the proportional offset in this control loop, as precise static pressure control is required in most cases. Usually derivative control action is not necessary, and the derivative weight should be input as 0. The system adds the static pressure offset value to the PID control calculation and usually remains at 0. The static pressure deadband value establishes a range above and below the static pressure setpoint where the error is considered 0. The deadband is applied above and below the static pressure setpoint. If the static sensor becomes unreliable, the command to the static pressure control device equals 0%. In the volume matching strategy, the return fan is to track the CFM delivery of the supply fan.


RFMSSFO

0

0

Static Integration Term

FailSoft

0

DelayOFFSupply Airflow

CFMCalculation

Supply VolumeVelocity Pressure SUB

Return Fan Offset



OffsetDeadband

AOReturnFanControl

CFMCalculation

Return Volume Velocity Pressure

Duct Area

Duct Area

Unocc CFM DifferentialOcc CFM Differential

Occupancy

Figure 48: Single Supply and Return Fan, Volume Matching, without Static Ramp

The controller uses the CFM differential as the setpoint, and calculates the controlled variable or feedback, by subtracting the return CFM from the supply CFM. The return volume proportional band integration value and derivative weight determines the gain of the return fan control loop. An integration value is always recommended to eliminate the proportional offset in this control loop, as precise volume control is required in most cases. Usually, derivative control action is not necessary and the derivative weight should be input as 0. If the return fan is started by means other than the AHU, supply fan status enables the return fan control integration. If the AHU supply fan is ramped on startup (supply or return started first), an active supply fan ramp or return fan status enables the return fan control integration. If the AHU starts the return fan first and there is no ramp of the supply fan on startup, the return fan integration is enabled for two minutes after the return fan command is on to allow for fan status to make. Return fan command and return fan not in alarm enables the return fan control integration. If the supply fan or return fan CFM calculation is unreliable, the output to the return fan equals 0%.


Single Supply, Low/High Speed Control This strategy controls a two speed fan motor. Upon startup, the low speed fan energizes. After a five minute delay the controller analyzes the velocity pressure of the supply air and allows the high speed circuit to energize. This strategy always starts the low speed fan first when a supply fan command is received.

BO13

Supply FanCommand

BOLow Speed

Five MinutesCoast Time

BOHigh SpeedDelay

OnAND Delay

On

Compare

Coast TimeTwo Minutes

ADD

DelayOff

NOT DelayOn

Supply VelocityPressure


Figure 49: Single Supply Fan; Low/High Speed Control If the velocity pressure is above the high speed velocity pressure setpoint, the controller commands the fan off, for the time period entered for coast time. After this timer expires, the high speed fan circuit energizes. When the velocity pressure decreases below the high speed velocity pressure setpoint minus the velocity pressure differential, the fan de-energizes again for a period equal to the coast time. When this timer expires, the low speed circuit fan energizes.

Constant Volume The fans start in the Occupied mode, Warmup mode, Vent or Purge mode, intermittent night operation, or setup/setback operation.


Using an AHU Application in a UNT Controller With HVAC PRO Release 5.10 or later, it is possible to select a UNT as a target device for an AHU application. Valid target devices include all UNT1nn-n controllers. With the 8 K UNTs, the question is not whether the configuration will fit in the controller, but if there are enough hardware points on the UNT for the configuration. Most likely, you will run out of Analog Output (AO) points first. If this is the case, you can use a Zone Bus actuator like the M100 motor actuator for the extra AOs.

Table 1: Default Zone Bus Addresses for Analog Outputs Output Address Damper Command 20 Preheat Valve 21 Heating Valve 22 Cooling Valve 23 Humid Valve 24 Supply Fan Cntl 25 Return Fan Cntl 26

The Zone Bus addresses listed in Table 1 are based on the default locations of analog outputs assigned by HVAC PRO during the Question and Answer session. If you move the analog output location within an HVAC PRO configuration, HVAC PRO will recalculate the Zone Bus address using the equation: ZB Address = AO Number + 19.

Default Point Types The AHU application Question and Answer session assigns point type defaults that are compatible with AHU controller hardware, but may not be compatible with UNT controller hardware. AHU controllers support the Current type for analog input sensors and analog output points. Since the Current type is not supported by the UNT controller hardware, any analog input sensor or analog output point configured as Current must be changed before targeting the application to a UNT controller. Voltage type is supported.


Instant Off Feature When using staged outputs in the UNT, the Binary Output (BO) Instant Off feature operates properly. So if the stages are on, and shutdown is turned on or airflow status is open, the staged outputs will ignore the minimum on timers and go off immediately. The Instant Off feature is also available on AHU controllers with firmware Revision C06 or later.

Momentary Start/Stop Momentary start/stop points will operate properly on the UNT controller when loaded with an AHU configuration.

Accumulator Point The accumulator point (BI-4) on the UNT controller operates as usual, even when the UNT controller is loaded with an AHU configuration.

Binary Parameters The locations of certain binary parameters loaded by the AHU application Question and Answer session are not supported by UNT1nn-0 devices. All UNT1nn-0 devices are removed from the Target Device Selection if you select anything but Hardware BI Point or Hardware AI Point to initiate any modes, as shown in Table 2.

Table 2: Mode/Command Mode/Command Name BD Address Cooling Lockout Cmd 205 Econ Switch 199 Heating Lockout Cmd 204 Occupied Command 196 Preht Lockout Cmd 203 Purge Command 194 Shutdown Command 197 Summer/Winter 198 Vent Command 193 Warmup/Cooldown Command 195

The following message will appear in the Reason Not Allowed window: Device UNT1nn-0 does not support BYTE (mode/command name) at address nnn. The location where these parameters would exist in the AHU controller is not supported in the UNT1nn-0.


Procedure Overview Table 3: Using AHU Applications To Do This Follow These Steps: Create a Mixed Air Single Path Application

From the File menu, select New. Select Air Handlers MA Single Path. Answer the questions as they are presented. When finished, go to the Economizer section.

Create a 100% Outside Air Single Path Application

From the File menu, select New. Select Air Handlers 100% OA Single Path. Answer the questions as they are presented. When finished, go to the Heat Recovery for 100% Outside Air section.

Create a Mixed Air Dual Path or 100% Outside Air Dual Path Application

From the File menu, select New. Select Air Handlers MA Dual Path or Air Handlers 100% OA Dual Path. Answer the questions as they are presented. After completing the Mixed Air Dual Path section of the question/answer path, go to the Economizer section. After completing the 100% Outside Air Dual Path section of the question/answer path, go to the Heat Recovery for 100% Outside Air section, since there is no Economizer available for 100% OA units.

Complete the Heat Recovery for 100% Outside Air Question/Answer Path

Answer the questions as they are presented. When finished, go to the Preheat section.

Complete the Economizer Question/Answer Path

Answer the questions as they are presented. When finished, go to the Minimum Duct Requirements section.

Complete the Minimum Duct Requirements Question/Answer Path

Answer the questions as they are presented. When finished, go to the Vent and Purge section.

Complete the Vent and Purge Question/Answer Path

Answer the questions as they are presented. When finished, go to the Preheat section.

Complete the Preheat Question/Answer Path

Answer the questions as they are presented. When finished, go to the Heating section.

Complete the Heating Question/Answer Path

Answer the questions as they are presented. After completing the Heating section of the question/answer path for none, modulated single coil, staged, or 2-position valve with face and bypass, go to the Cooling section. After completing the Heating section of the question/answer path for modulated common heating and cooling coil, go to the Dehumidification section.

Complete the Cooling Question/Answer Path

Answer the questions as they are presented. After completing the Cooling section of the question/answer path for None, go to the Humidification section. For all other cooling strategies, go to the Dehumidification section.

Complete the Dehumidification Question/Answer Path

Answer the questions as they are presented. When finished, go to the Humidification section.

Complete the Humidification Question/Answer Path

Answer the questions as they are presented. When finished, go to the Modes of Operation section.

Complete the Modes of Operation Question/Answer Path

Answer the questions as they are presented.

Complete the Fan System Control Question/Answer Path

Answer the questions as they are presented.


Detailed Procedures Creating a Mixed Air Single Path Application

To create a mixed air single path application: 1. From the File menu, select New. 2. Select Air Handlers MA Single Path. 3. Answer the questions as they are presented (Figure 50), using the

control strategy information in the Key Concepts section and the information presented in the remainder of this procedure as a guide.

4. After the Mixed Air Single Path section, the question/answer path continues on to the Economizer section.

Select the Control Strategy

No Remote Setpoint

Slider

MASP

Supply Air Resetfrom Return Temperature

RoomControl

Supply Air Reset from Zone

Temperature

Room Controlof Cooling

Room Reset of Heating

ConstantDischarge AirTemperature

Return AirControl

SingleZone Setpoint

DualZone Setpoints

Is a RemoteZone Setpoint

Needed?

Are Remote ZoneSetpoints forHeating and

Cooling Needed?

ToEconomizer

Section

TMZ Digital Room Sensor

No Dual Remote Setpoint Sliders

TMZ Digital RoomSensor

No Remote Setpoint

Slider

Is a RemoteZone Setpoint

Needed?


Select the Setpoint Type

Figure 50: Mixed Air Single Path Questions and Answers


Select the Control Strategy See the Key Concepts section for descriptions of each of the control strategy options.

Select the Setpoint Type Choose among the options in Table 4.

Table 4: Select the Setpoint Type Option Description Single Zone Setpoint

Single setpoint uses a zone setpoint and a deadband. When the zone temperature is within the heating deadband, the zone heating and cooling commands are 0%.

Dual Zone Setpoints

The dual setpoints strategy uses separate cooling and heating setpoints. When the zone temperature is between the cooling and heating setpoints, the zone heating and cooling commands are 0%.

Is a Remote Zone Setpoint Needed? Choose among the options in Table 5.

Table 5: Is a Remote Zone Setpoint Needed? Option Description No The zone setpoint and heating deadband used for sequencing

heating and cooling outputs for all modes of operation are defined in HVAC PRO.

Remote Setpoint Slider

An AI is defined as the remote zone setpoint. A single cooling setpoint adjustment from a room thermostat is used to establish the zone setpoints for sequencing heating and cooling during the Occupied mode. The unoccupied and standby setpoints defined in HVAC PRO are used during the Unoccupied and Standby modes. If the remote AI becomes unreliable, the controller will use the occupied zone setpoints defined in HVAC PRO.


Points, parameters and logic are assigned to provide setpoints adjustable from a either a supervisory system, a configuration/commissioning tool, or a TMZ Digital Room Sensor. The heating and cooling setpoints are adjustable from the supervisory system, configuration/commissioning tool or TMZ. The Heating Setpoint and Cooling Setpoint are adjustable with default values of 20°C (68.0°F) and 22°C (72°F) respectively. Additional parameters are loaded to provide information for the TMZ to display to the user.


Are Remote Zone Setpoints for Heating and Cooling Needed? Choose among the options in Table 6.

Table 6: Are Remote Zone Setpoints for Heating and Cooling Needed? Option Description No The zone setpoints used for sequencing heating and cooling

outputs for all modes of operation are defined in HVAC PRO. Dual Remote Setpoint Sliders

Two AIs are defined as the heating and cooling setpoints. Separate heating and cooling setpoint adjustments are used to establish the zone setpoints for sequencing heating and cooling during the Occupied mode. The unoccupied and standby setpoints defined in HVAC PRO are used during Unoccupied and Standby modes. If the remote AI becomes unreliable, the controller will use the occupied zone setpoints defined in HVAC PRO.

TMZ Remote Digital Sensor

Points, parameters and logic are assigned to provide setpoints adjustable from a either a supervisory system, a configuration/commissioning tool, or a TMZ digital room sensor. The heating and cooling setpoints are adjustable from the supervisory system, configuration/commissioning tool or TMZ. The Heating Setpoint and Cooling Setpoint are adjustable with default values of 20°C (68°F) and 22°C (72°F) respectively. Additional parameters are loaded to provide information for the TMZ to display to the user.


Creating a 100% Outside Air Single Path Application To create a 100% outside air single path application: 1. From the File menu, select New. 2. Select Air Handlers 100% OA Single Path. 3. Answer the questions as they are presented (Figure 51), using the

information presented in the Key Concepts section and the Mixed Single Air Path Applications topic as a guide.

4. After the 100% Outside Air Single Path section, the question/answer path continues on to the Heat Recovery for 100% Outside Air section.

100OASP

Select the Setpoint Type

RoomControl

RoomControl Cooling

Room ResetHeating

Supply AirReset FromZone Temp

ExhaustAir TempControl

ConstantDischarge

Air Temperature

Single ZoneSetpoint

Dual ZoneSetpoints

Is a Remote ZoneSetpoint Needed?

Are Remote ZoneSetpoints forHeating and

Cooling Needed?

Select the Control Strategy

To Heat Recovery

Section

No Remote Setpoint Slider


No Dual Remote Setpoint Sliders


Figure 51: 100% Outside Air Single Path Questions and Answers


Creating a Mixed Air Dual Path or 100% Outside Air Dual Path Application

To create a mixed air dual path or 100% outside air dual path application: 1. From the File menu, select New. 2. Select Air Handlers MA Dual Path or Air Handlers 100% OA

Dual Path. 3. Answer the questions as they are presented (Figures 52 and 53),

using the information presented in the Key Concepts section as a guide.

4. After the Mixed Air Dual Path section, the question/answer path continues on to the Economizer section. After the 100% Outside Air Dual Path section, the question/answer path continues on to the Heat Recovery for 100% Outside Air section, since there is no Economizer available for 100% OA units.

Mixed Air Dual Path

To Economizer Section

MultizoneHot/Cold

Deck Reset

MultizoneZone Control

Dual DuctHot/Cold

Deck Reset

Dual DuctZone Control

MADP

Figure 52: Mixed Air Dual Path Questions and Answers

100% Outside Air Dual Path

To Heat Recovery Section

MultizoneHot/Cold

Deck Reset

MultizoneZone Control

Dual DuctHot/Cold

Deck Reset

Dual DuctZone Control

100OADP

Figure 53: 100% Outside Air Dual Path Questions and Answers


Completing the Heat Recovery for 100% Outside Air Question/Answer Path

To complete the heat recovery for 100% outside air question/answer path: 1. Answer the questions as they are presented (Figure 54), using the

information presented in the Key Concepts section and the remainder of this procedure as a guide.

2. After the Heat Recovery for 100% Outside Air section, the question/answer path continues on to the Preheat section.

HEATREC

None

Select the Analog Input

No Yes

Maintained MomentaryPulse

ToPreheatSection

Select the Type of Heat Recovery Device:

2 Pos Output fromAnalog Input Sensor

OutdoorAir Sensor

DischargeAir Sensor

Run AroundGlycol Loop

Type of PumpOutput

Is pump start neededupon sensor entering

prop band?

Figure 54: Heat Recovery for 100% Outside Air Questions and Answers


Select the Heat Recovery Type Choose among the options in Table 7.

Table 7: Select the Heat Recovery Type Option Description None No point/parameter assignment or logic sequence for this

selection. 2-Position Output from Analog Input Sensor

See the Key Concepts section for a description of this option.

Run Around Glycol Loop


Is Pump Start Needed upon Sensor Entering Prop Band? Choose among the options in Table 8.

Table 8: Is Pump Start Needed upon Sensor Entering Prop Band? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes The pump start option allows a pump operation whenever the

command to the heat recovery device is greater than 1% open.

Type of Pump Output Choose among the options in Table 9.

Table 9: Type of Pump Output Option Description Maintained A single binary output is assigned. It will be energized when the

pump command is on and de-energized when the pump command is off.

Momentary Pulse

A pair of binary outputs are assigned. The start output will be energized momentarily when the pump command is on and the stop output will be energized momentarily when the pump command is off. A momentary output has a pulse duration of 1.5 seconds.


Completing the Economizer Question/Answer Path To complete the economizer question/answer path: 1. Answer the questions as they are presented (Figure 55), using the


2. After the Economizer section, the question/answer path continues on to the Minimum Duct Requirements section.

Select Damper Control Strategy

Which setpoint shall be used?

No

Select The Economizer Switchover Strategy

None Dry Bulb

ToMinimum DuctRequirements

Section

Yes

Separate Mixed Air Closed Loop Sequenced with Heatingand Cooling

Is a Mixed AirLow LimitRequired?

SeparateMixed Air Setpoint

DischargeAir Setpoint

(Cold Deck forDual Path)

Only Asked If Strategy isDischarge Control or

Supply Air Reset

Software(N2) Command

HardwareBI point

EnthalpyComparison

Outdoor AirEnthalpy

FixedTemperatureDifferential

ECON

NoYes

Is Low Limit Override of Minimum Required?

Figure 55: Economizer


Select the Damper Control Strategy Choose among the options in Table 10.

Table 10: Select the Damper Control Strategy Option Description Separate Mixed Air Closed Loop

This strategy provides a separate control loop for the outdoor air dampers based on the mixed air sensor. A temperature setpoint is selected and maintained when free cooling is available and economizer is on. The direct acting output shall open the outside air dampers from minimum position to 100% as the mixed air temperature rises through the proportional band. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control.

Sequenced with Heating and Cooling

This strategy allows the sequencing of the outside air dampers with the mechanical cooling device when free cooling is available and economizer is on. The direct acting output shall open the outside air dampers from minimum position to 100% as the controlled temperature rises through the economizer proportional band. The economizer proportional band must not exceed the sum of the cooling deadband and the cooling proportional band. If this is not done, the economizer output will stop increasing when the cooling output reaches 100%. When the Economizer mode is off (free cooling not available), an alternate cooling deadband is used to shift the cooling proportional band left towards the control setpoint. This causes mechanical cooling to modulate or energize at a temperature closer to the control setpoint in comparison to the normal cooling deadband when free cooling is available. The cooling integration term for the mechanical cooling device is also used by the economizer dampers.

Which Setpoint Shall Be Used? Choose among the options in Table 11.

Table 11: Which Setpoint Shall Be Used? Option Description Separate Mixed Air Setpoint

A mixed air setpoint shall be added to the parameters list for mixed air temperature control.

Discharge Air Setpoint (Cold Deck for Dual Path)

The mixed air closed loop will maintain the same setpoint as the discharge or supply air loop (cold deck for dual path). The actual mixed air setpoint will be available for the user to monitor.


Is a Mixed Air Low Limit Required? Choose among the options in Table 12.

Table 12: Is a Mixed Air Low Limit Required? Option Description Yes A mixed air temperature sensor will be assigned to an AI and will

be used to maintain the low limit logic for the economizer cycle. Control will be achieved through a reverse acting PI algorithm that will back off the economizer command and position the damper to maintain the low limit setpoint. The mixed air low limit control will override the minimum position setting if the mixed temperature continues to drop below setpoint which can occur with low ambient conditions in the outdoor air. If you desire a minimum position regardless of the mixed air low limit logic (for example, you are not in danger of freezing mechanical equipment), use a damper offset which will not allow the damper to go below this value during Occupied mode. Integration has been added to this control loop to eliminate the inherent offset associated with proportional only control.

No No point/parameter assignment or logic sequence for this selection.

Is Low Limit Override of Minimum Required? Choose among the options in Table 13.

Table 13: Is Low Limit Override of Minimum Required? Option Description Yes A mixed air temperature sensor will be assigned to an AI and will

be used to maintain the low limit logic for the economizer cycle. Control will be achieved through a reverse acting PI algorithm that will back off the economizer command and position the damper to maintain the low limit setpoint. The mixed air low limit control will override the minimum position setting if the mixed temperature continues to drop below setpoint which can occur with low ambient conditions in the outdoor air. Integration has been added to this control loop to eliminate the inherent offset associated with proportional only control.

No No point/parameter assignment or logic sequence for this selection.

Select Economizer Switchover Strategy See the Key Concepts section for a description of the economizer switchover strategy options.


Completing the Minimum Duct Requirements Question/Answer Path

To complete the minimum duct requirements question/answer path: 1. Answer the questions as they are presented (Figure 56), using the

information presented in the remainder of this procedure as a guide.

2. After the Minimum Duct Requirements section, the question/answer path continues on to the Vent and Purge section.

Is a Separate Minimum Duct used for minimum position?

No

2 Position

Pitot Tube0%

Yes

How Is the Minimum DamperControlled

Minimum Closed LoopVolume Control

Select Type of Air Flow Measuring

Station

Scaled Input-Flow StationThermistor

Is Minimum Damper PositionReset from an Air Quality

Sensor Needed?

MinimumPosition

Last ReliableCommand

For Unreliable Outdoor Airor Control Sensor

Command Outdoor Air Damper to:

For Unreliable Outdoor Airor Control Sensor

Command Outdoor Air Damper to:

Is Minimum Damper PositionReset from an Air Quality Sensor

Needed?

ToVent and Purge

Section

No Yes

No Yes

0%MinimumPosition

Last ReliableCommand

MINDUCT

Figure 56: Minimum Duct Requirements


Is a Separate Minimum Duct Used for Minimum Position? Choose among the options in Table 14.

Table 14: Is a Separate Minimum Duct Used for Minimum Position? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes A minimum damper control strategy must be selected by the user,

either 2-position or minimum closed loop volume control. See How is the Minimum Damper Controlled? for logic and point assignments.

Is Minimum Damper Position Reset from an Air Quality Sensor Needed? Choose among the options in Table 15.

Table 15: Is Minimum Damper Position Reset from an Air Quality Sensor Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes An input from an air quality sensor resets the minimum position of

the outdoor air damper to an increased value (Figure 57). The controller does this through the inputs of indoor air quality low limit and indoor air quality reset band. These inputs adjust the minimum position setpoint from minimum position through the minimum position reset band. The indoor air quality defaults are in reference to a carbon dioxide sensor that indicates Parts Per Million (PPM). The minimum position reset schedule is in percent position or CFM, depending upon the type of minimum damper strategy selected. High carbon dioxide is usually a good indication that more outside air is required. However, low carbon dioxide is not always a good indication of contaminant free air.

IAQ2

Occupied

Air Quality SensorAir Quality Low Limit

Air Quality Reset BandMinimum Position

Minimum Reset Band

Reset

IAQ Minimum Setpoint

Minimum Position

(% or CFM)

0

12

34 1 2

3

4

Figure 57: Minimum Damper Reset from Air Quality Sensor


For Unreliable Outdoor Air or Control Sensor, Command Outdoor Air Damper To Choose among the options in Table 16.

Table 16: For Unreliable Outdoor Air or Control Sensor, Command Outdoor Air Damper To Option Description Minimum Position

Drive the damper to the minimum position.

0% Drive the damper to the 0% open position. Last Reliable Command

Hold the output at the last reliable position.

How is the Minimum Damper Controlled? Choose among the options in Table 17.

Table 17: How is the Minimum Damper Controlled? Option Description 2-Position The 2-position strategy energizes a binary output whenever the

controller switches into the Occupied mode of operation (Figure 58). During the Unoccupied or Shutdown mode, the binary output for 2-position control is off. During the Vent or Purge mode, the controller energizes the binary output (damper) even if the controller is in the Unoccupied mode.

Minimum Closed Loop Volume Control

The minimum volume closed loop strategy allows control to a minimum air volume setpoint (CFM) via conventional PI control (Figure 59). As the volume (CFM) of air through an airflow measuring station decreases below the minimum volume setpoint and into the CFM proportional band, the minimum damper is modulated open. The CFM deadband suspends any change in the control output when the actual CFM is within the this deadband region. The full input deadband value is in effect on the positive and negative side of the CFM setpoint. Integration may be added to this control loop to eliminate the inherent offset associated with proportional only control. The minimum duct area input is the square foot area of the airflow measuring station (provided by device manufacturer). The area is required by the controller to calculate the CFM. The CFM offset, is a value in percent that the controller adds to the command after it performs the proportional and integration control calculation.

Occupied

AirflowPurge Vent

BO

Shutdown

0 SMD2PDNOTWarmup

OR OR OR AND

Figure 58: 2-Position Minimum Damper


MPMCLD2CFM = (Velocity) x (ft )2

CFM Integration

AI Linearized Velocity Input

AIMinimum Damper

Airflow

Supply Air Commandv

ORNOT

CFMCalculation

(Linear)

PI Control

NOT OR

From Air Quality Reset Logic

(If Used)

00 or100

FailSoft 0

CFMCalculation

P

Airflow Shutdown

0Duct Area (ft )2

Constant (K)Duct Area (ft )2

CFM = 4005( P /K ) (ft ) 2

AI Velocity Pressure

Minimum Volume CFM Setpoint

CFM Proportional BandCFM Integration

CFM OffsetCFM Deadband

1

2

12

Figure 59: Minimum Volume Closed Loop Application

Select the Type of Air Flow Measuring Station Choose among the options in Table 18.

Table 18: Select the Type of Air Flow Measuring Station Option Description Pitot Tube This selection is required when the controller needs to calculate

the square root of the velocity pressure reading. The area of the face of the airflow station is required, and a constant is required to extract any amplification of the velocity pressure that is present in the design of the Pitot tube traverse. The formula for the CFM calculation of the Pitot tube method is:

KPv4005ACFM ∗∗=

Where: Pv = velocity pressure (in. WG) K = constant (provided by the manufacturer) A = area of the airflow station (sq ft)

Scaled Input-Flow Station (Thermistor)

This selection is intended for a packaged airflow station having a linear output ranged in velocity (FPM) or volume (CFM). In cases where the airflow station outputs a linear CFM signal, adjust the value for the area of the airflow measuring station to 1.0. CFM = (V)(A) Where: V = velocity (ft/min) A = area of the airflow station (sq ft)


Completing the Vent and Purge Question/Answer Path To complete the vent and purge question/answer path: 1. Answer the questions as they are presented (Figure 60), using the


2. After the Vent and Purge section, the question/answer path continues on to the Preheat section.

Is Vent and Purge Mode Needed?

No

Select the Method to Control the Vent Mode:

Select the Method to Control the Purge Mode:

To Preheat Section

Yes


HardwareBI point

Both withBI backup

Both canactivate

VENTPURG


HardwareBI point

Both withBI backup

Both canactivate

Figure 60: Vent and Purge


Is Vent and Purge Mode Needed? Choose among the options in Table 19.

Table 19: Is Vent and Purge Mode Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes The Vent and Purge modes open the outdoor air damper to 100%

when the controller commands it to on. The difference between the two modes is purge shuts off all mechanical heating, cooling, and humidification while vent allows all heating, cooling, and humidification to remain in control. If the controller commands Vent and Purge modes on simultaneously, Vent mode takes priority. Both modes are active during Occupied or Unoccupied modes of operation but are not effective during the Shutdown mode. The outdoor air dampers will not open until the supply airflow status is on. Either mode energizes the supply fan start command.

Select the Method to Control the Vent Mode Choose among the options in Table 20.

Table 20: Select the Method to Control the Vent Mode Option Description Software (N2) Command

A Vent mode binary data point is provided for a Facility Management System (FMS) to command. If communications are lost with the FMS, the controller will maintain the last commanded state for ten minutes. The default of the Vent mode is off.

Hardware BI Point

A hardware binary input is provided to switch the controller into the Vent mode; when the contact is closed, the Vent mode will be active.

Both with BI Backup

A Vent mode binary data point is provided for a facility management system to command. If communication with the FMS is lost, the status of the binary input is used to determine Vent mode.

Both can Activate

A Vent mode binary data point is provided for a facility management system to command. A hardware binary input is also provided to switch the controller into Vent mode. Either point can place the controller into the Vent mode. Both points must be off for the controller to release to the previous mode.


Select the Method to Control the Purge Mode Choose among the options in Table 21.

Table 21: Select the Method to Control the Purge Mode Option Description Software (N2) Command

A Purge mode binary data point is provided for a facility management system to command. If communication is lost with the FMS, the controller will maintain the last commanded state for ten minutes. The default of the Purge mode is off.

Hardware BI Point

A hardware binary input is provided to switch the controller into the Purge mode; when the contact is closed, the Purge mode will be active.

Both with BI Backup

A Purge mode binary data point is provided for a facility management system to command. If communication with the FMS is lost, the status of the binary input is used to determine Purge mode.

Both can Activate

A Purge mode binary data point is provided for a facility management system to command. A hardware binary input is also provided to switch the controller into Purge mode. Either point can place the controller into the Purge mode. Both points must be off for the controller to release to the previous mode.

Completing the Preheat Question/Answer Path To complete the preheat question/answer path: 1. Answer the questions as they are presented (Figure 61), using the


2. After the Preheat section, the question/answer path continues on to the Heating section.


PREHEAT

Select Type of Preheat Control Strategy

No Yes

None

0% 100%

Software (N2) Command

HardwareAI point

Both withAI backup

0% 100%

0% 100%

Is pump start upon a preheat command needed?

No Yes

Type of Output Signal

Maintained

0% 100%

No Yes

0% 100% Last Reliable Command

To Heating Section


HardwareAI point

Both withAI backup

Should the Preheat output gogo to 0% during Shutdown?*

Yes Use loss of airflow defaults

Should the Preheat output go to 0% during Shutdown?


Is Preheat Lockout from outdoor air temperature needed ?

Should the Preheat outputgo to 0% during Shutdown?*


Upon loss of air flow, the valve will be commanded to:

2 Pos Steam/WaterValve (Sensor Cntl'd)

Enter the ControlSensor

OutdoorAir

MixedAir

DischargeAir

Upon loss of air flow, the valve will be commanded to:

Remain inControl

Is Preheat Lockout from outdoor air temperature needed?

Select the MethodTo Initiate Preheat Lockout

If the control sensor becomes unreliable,

command preheat valve to:

Face/Bypass w/vlvSwitch over Seq w/Htg Clg*

Upon loss of airflow,the value will be commanded to:

Remain inControl

Select the Methodto Initiate Preheat Lockout


command preheat valve to:

ModulatedSingle Coil

Select thePreheat Control

Strategy

Closed Loopwith separate

sensor

Sequenced with Heating and Cooling*

Remain inControl

MomentaryPulse

G

H

* Not an option on dual path units

Figure 61: Preheat


Figure 62: Preheat (Cont.)


Select the Type of Preheat Device Choose among the options in Table 22.

Table 22: Select the Type of Preheat Device Option Description None No point/parameter assignment or logic sequence for this

selection. 2-Position Steam/Water Valve (Sensor Cntl’d)


Face and Bypass w/Vlv Switch over Seq w/Htg Clg


Modulated Single Coil


Staged See the Key Concepts section for a description of this option.

Enter the Control Sensor (2-Position Only) Choose among the options in Table 23.

Table 23: Enter the Control Sensor (2-Position Only) Option Description Outdoor Air When the outdoor air temperature falls below the preheat low limit

setpoint, the controller commands a binary output to on. When the outdoor air temperature rises above the preheat low limit setpoint plus the differential, the BO will be commanded off.

Mixed Air When the mixed air temperature falls below the preheat low limit setpoint, the controller commands a binary output to on. When the mixed air temperature rises above the preheat low limit setpoint plus the differential, the BO will be commanded off.

Discharge Air

When the discharge air temperature falls below the preheat low limit setpoint, the controller commands a binary output to on. When the discharge air temperature rises above the preheat low limit setpoint plus the differential, the BO will be commanded off.


Should the Preheat Command Go to 0% on Shutdown? Choose among the options in Table 24.

Table 24: Should the Preheat Command Go to 0% on Shutdown? Option Description Yes When the Shutdown mode is on, the controlled device will be

commanded to 0%. Use Loss of Airflow Defaults

The Shutdown mode will have no effect on the controlled device. Shutdown will turn the fan off causing the loss of airflow. The position of the controlled device will be determined by how the Loss of Air Flow question is answered.

Upon Loss of Air Flow, the Valve will be Commanded To Choose among the options in Table 25.

Table 25: Upon Loss of Air Flow, the Valve will be Commanded To Option Description 0% Drive the preheat valve to the 0% open position and bypass

damper to 0%. 100% Drive the preheat valve to the 100% open position and bypass

damper to 0%. Remain In Control

Continue to control as normal. This strategy is intended to be used only where the coil has an effect on the sensor when airflow is off, that is the sensor is in close proximity to the coil.

Is Preheat Lockout from Outdoor Air Temperature Needed? Choose among the options in Table 26.

Table 26: Is Preheat Lockout from Outdoor Air Temperature Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes All preheat control strategies may be locked out. The preheat

lockout can be initiated from a controller input, or over the N2 Bus by a FMS.


Select the Method to Initiate Preheat Lockout

HeatingLockout

N2 Command


Differential

Compare

HeatingLockout


Differential

Compare


AI Switch

N2 Com Status

N2 Command

HeatingLockout

CommandLOCKOUT

Figure 63: Lockout Choose among the options in Table 27.

Table 27: Select the Method to Initiate Preheat Lockout Option Description Software (N2) Command

A binary data point is provided to initiate the preheat lockout. If communication is lost with the FMS, the controller will maintain the last commanded state for ten minutes. The default of the preheat lockout is off.

Hardware AI Point

An analog input is assigned for an outside air temperature sensor. When the outside air temperature is above the preheat lockout setpoint, the preheat will be locked out; when the outside air temperature is below the setpoint minus the differential, the preheat will be enabled. If the analog input becomes unreliable, the preheat will failsoft enabled.

Both with AI Backup

A binary data point is provided to initiate the preheat lockout. If communication is lost with the FMS, the controller will use the outside air sensor as a backup for the preheat lockout decision. In the event N2 communications is lost, when the outside air temperature is above the preheat lockout setpoint, the preheat will be locked out; when the outside air temperature is below the setpoint minus the differential, the preheat will be enabled. If the analog input becomes unreliable, the preheat will failsoft enabled.


If the Control Sensor Becomes Unreliable, Command Preheat Valve To Choose among the options in Table 28.

Table 28: If the Control Sensor Becomes Unreliable, Command Preheat Valve To Option Description 0% Drive the valve to the 0% open position. 100% Drive the valve to the 100% open position. Last Reliable Command

Hold the output at the last reliable position. This option is not available on a 2-position steam strategy.

Is Pump Start upon a Preheat Command Needed? Choose among the options in Table 29.

Table 29: Is Pump Start upon a Preheat Command Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes Preheat Control Strategies “Face and Bypass Valve Sequenced

with Heating and Cooling” and “Modulated Single Coil” have the option of an additional output assigned for a pump. This output will be energized when the heating command is greater than 1%.

Type of Output Signal Choose among the options in Table 30.

Table 30: Type of Output Signal Option Description Maintained A single binary output is assigned. It will be energized when the


Momentary Pulse



Select the Preheat Control Strategy (Staged and Modulated) Choose among the options in Table 31.

Table 31: Select the Preheat Control Strategy (Staged and Modulated) Option Description Closed Loop with Separate Sensor

When configured as a closed loop, the preheat setpoint with separate sensor, the preheat setpoint, proportional band, integration value, offset, and deadband control the action of the preheat device.

Part of Main Ctl Sequenced with Heating and Cooling

When configured as sequenced with heating and cooling, the preheat proportional band allows the preheat device to be controlled as the control temperature decreases below the control setpoint. The integration term is shared with the heating device. This option is not available on Dual Path units.

Sequencer - Number of Stages See the Key Concepts section for a description of these options.

Is Vernier Control Needed? (AO Control for % after Stage) Choose among the options in Table 32.

Table 32: Is Vernier Control Needed? (AO Control for % after Stage) Option Description No No point/parameter assignment or logic sequence for this

selection. Yes This strategy allows an analog output to be commanded from 0 to

100% between each stage of preheat. The analog command increases from 0 to 100% as the sequencer command from the control strategy increases from 0 to the starting point of the first stage. When you select Vernier control, the starting point of the first stage defaults to the normal proportional division of the number of stages plus one (i.e., 3 stages would start at 25, 50, and 75% commands). When the sequencer preheat command rises above the first stage on percent, the analog command begins again at 0 and increases to 100% until the sequencer command equals the starting point of the second stage. The analog output operation between each stage is consistent between all stages. The Vernier control strategy cannot be used with rotational sequencing.


Is Rotational Sequencing Needed? Choose among the options in Table 33.

Table 33: Is Rotational Sequencing Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes The rotational sequencing option allows each stage to be the next

started (in order) after the controller turns off the first stage. For example, if Stages 1 - 2 - 3 - 4 energize and then turn off in the opposite order, the next sequence is 2 - 3 - 4 - 1. This new order de-energizes in reverse, and then reorders as 3 - 4 - 1 - 2. When you select the rotational sequencing feature, you cannot use Vernier control.

Completing the Heating Question/Answer Path To complete the heating question/answer path: 1. Answer the questions as they are presented (Figure 64), using the


2. After the Heating section, the question/answer path continues on either to the Cooling section (for Heating device=None, Modulated single coil, Staged, or 2-Position valve with face and bypass) or the Dehumidification section (for Heating device= Modulated common heating and cooling coil).


Select the type of heating device:

None Modulatedsingle coil

Modulated common htg and clg coil

Staged 2 Position valve w/face and bypass

B C

No Yes

Will pump startupon heating commandgreater than 0% open?

Type of output signal:

Maintained Momentarypulse

No Yes

Is outdoor air lockoutof heating needed?

Select the method to initiate

Heating Lockout:

If the control sensor becomes unreliable, command heating valve to:

0% 100% Last Reliable command

Upon loss of air flow, the heating valve will be commanded to:

0% 100% Remain in Control

A

Method of determining heating or cooling:

Software(N2)

command

Hardware BI point

HardwareAI point

Will pump start upon a htg/clg command greater

than 0% open?

No Yes



No Yes



Heating Lockout:

D

Software(N2)

command

Hardware BI point

HardwareAI point

Software(N2)

command

Hardware BI point

HardwareAI point


Should the heating output go to 0% during shutdown

AHUHTG1

Position AdjustIncremental

Figure 64: Heating


B

No Yes



Heating Lockout:

Sequencer: No. of Stages

One Two thru Nine

Is Vernier control needed (AO control

for % control between stages)?

No Yes


for % control after stage)?

No Yes

Is rotational sequencing

needed?

No Yes


command heating valve to:


Does the electric heat require a 2 position command to face and bypass damper?

No Yes

A



C

No Yes



Heating Lockout:


command heating valve to:


Upon loss of air flow, the heating valve will be commanded to:


To Cooling Section AHUHTG2


Should the heating output go to 0% during shutdown?

Software(N2)

command

Hardware BI point

HardwareAI point

Software(N2)

command

Hardware BI point

HardwareAI point

Figure 65: Heating (Cont.)



command htg/clg valve to:


Upon loss of air flow, the htg/clg valve will be commanded to:


To Dehumidification

Section

D

AHUHTG3

No Yes

Is outdoor air lockoutof cooling needed?


Cooling Lockout:

Software(N2)

command

Hardware BI point

HardwareAI point


Should the htg/clg output go to 0% during shutdown?

Figure 66: Heating (Cont.)


Select the Type of Heating Device Choose among the options in Table 34.

Table 34: Select the Type of Heating Device Option Description None No point/parameter assignment or logic sequence for this

selection. Modulated Single Coil


Modulated Common Htg and Clg Coil


Staged See the Key Concepts section for a description of this option. 2-Position Valve w/Face and Bypass


Position Adjust – Incremental


Will Pump Start Upon a Heating Command Greater than 0% Open? Choose among the options in Table 35.

Table 35: Will Pump Start Upon a Heating Command Greater than 0% Open? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes The heating control strategies titled “Modulated Single Coil,”

“Common Heating and Cooling,” and “2-Position Face and Bypass Valve” have the option of an additional output assigned for a pump. This output will be energized when the heating command is greater than 1%.





Momentary Pulse


Is Outdoor Air Lockout of Heating Needed? Choose among the options in Table 37.

Table 37: Is Outdoor Air Lockout of Heating Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes All heating control strategies may be locked out. The heating

lockout can be initiated from a controller input or over the N2 Bus by an FMS.

HeatingLockout

N2 Command


Differential

Compare

HeatingLockout


Differential

Compare


AI Switch

N2 Com Status

N2 Command

HeatingLockout

CommandLOCKOUT

Figure 67: Heating Lockout


Select the Method to Initiate Heating Lockout Choose among the options in Table 38.

Table 38: Select the Method to Initiate Heating Lockout Option Description Software (N2) Command

A binary data point is provided to initiate the heating lockout (Figure 67). If communication is lost with the FMS, the controller will maintain the last commanded state for ten minutes. The default of the heating lockout is off.

Hardware BI Point

A hardware binary input is provided to initiate heating lockout. When the contact is closed, heating lockout is initiated.

Hardware AI Point

An analog input is assigned to outdoor air temperature, for when the outside air temperature drops below the heating lockout setpoint and differential. If the analog input becomes unreliable, the heating will failsoft enabled.

If the Control Sensor Becomes Unreliable, Command Heating Valve To Choose among the options in Table 39.

Table 39: If the Control Sensor Becomes Unreliable, Command Heating Valve To Option Description 0% Drive the valve to the 0% open position. 100% Drive the valve to the 100% open position. Last Reliable Command


Should the Heat Command go to 0% on Shutdown? Choose among the options in Table 40.

Table 40: Should the Heat Command go to 0% on Shutdown? Option Description Yes When the Shutdown mode is on, the controlled device will be




Upon Loss of Air Flow, the Heating Valve will be Commanded To Choose among the options in Table 41.

Table 41: Upon Loss of Air Flow, the Heating Valve will be Commanded To Option Description 0% Drive the valve to the 0% open position. 100% Drive the valve to the 100% open position. Remain In Control


Method of Determining Heating or Cooling Choose among the options in Table 42.

Table 42: Method of Determining Heating or Cooling Option Description Software (N2) Command

A binary data point is provided to initiate the heating/cooling switchover. If communication is lost with the FMS, the controller will maintain the last commanded state for ten minutes. The default of the sum/win is off, which will leave the AHU in Summer mode for cooling. The controller is in the Winter mode of operation when sum/win = on (1) and in the Summer mode when it is off (0).

Hardware BI Point

A binary input is provided to initiate the heating/cooling switchover. The controller is in the Winter mode of operation when sum/win = on (BI contact is closed) and in the Summer mode when it is off (BI contact is open).

Hardware AI Point

An analog input is assigned as a hot/cold water temperature sensor. The controller is in the Winter mode of operation when sum/win = on and in the Summer mode when it is off. When the AI is greater than the setpoint, sum/win = on and when the AI is less than the setpoint minus the differential, sum/win = off. The default setpoint differential is 7°C (40°F), and should remain a relatively large value if adjusted.



Is Vernier Control Needed (AO Control for % Control Between Stages) Choose among the options in Table 43.

Table 43: Is Vernier Control Needed (AO Control for % Control Between Stages) Option Description No No point/parameter assignment or logic sequence for this


100% between each stage of heating. The analog command increases from 0 to 100% as the sequencer command from the control strategy increases from 0 to the starting point of the first stage. When you select Vernier control, the starting point of the first stage defaults to the normal proportional division of the number of stages plus one (i.e., 3 stages would start at 25, 50, and 75% commands). When the sequencer heating command rises above the first stage on percent, the analog command begins again at 0 and increases to 100% until the sequencer command equals the starting point of the second stage. The analog output operation between each stage is consistent between all stages. The Vernier control strategy cannot be used with rotational sequencing.




started (in order) after the controller turns off the first stage. For example, if Stages 1 - 2 - 3 - 4 energize and then turn off in the opposite order, the next sequence is 2 - 3 - 4 - 1. This new order de-energizes in reverse, and then reorders as 3 - 4 - 1 - 2. When you select the rotational sequencing feature, you cannot use Vernier control.


Does the Electric Heat Require a 2-Position Command to Face and Bypass Damper? Choose among the options in Table 45.

Table 45: Does the Electric Heat Require a 2-Position Command to Face and Bypass Damper? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes A binary output is assigned as a heat face/bypass. This output will

turn on when the heating command reaches 11% and goes back off at 1%.

Select Output Type Choose among the options in Table 46.

Table 46: Select Output Type Option Description Maintained A single binary output is assigned. It will be energized when the

valve is commanded open and de-energized when the valve is commanded closed.

Momentary Pulse

A pair of binary outputs are assigned, the open output will be energized momentarily when the valve is commanded open and the close output will be energized momentarily when the valve is commanded closed. A momentary output has a pulse duration of 1.5 seconds.

Completing the Cooling Question/Answer Path To complete the cooling question/answer path: 1. Answer the questions as they are presented (Figure 68), using the


2. After the Cooling section, the question/answer path continues on either to the Humidification section (Cooling device = None) or to the Dehumidification section (all other cooling devices).


Select the type of cooling device:

None Modulatedsingle coil

Staged 2 Position valve w/face and bypass

If the control sensor becomes unreliable, the cooling valve

is commanded to:


If the control sensor becomes unreliable, the cooling stages are commanded to:


To Dehumidification

Section

Upon loss of air flow, the cooling valve will be commanded to:


No Yes

Is pump startupon cooling command

greater than 0% needed?



No Yes



Cooling Lockout:


HardwareAI point

Both withAI backup

No Yes



Cooling Lockout:

Sequencer: No of Stages

One Two through Nine


for % control between stages)?

No Yes


for % control after stage)?

No Yes

Is rotational sequencing

needed?

No Yes

No Yes



Cooling Lockout:

Upon loss of air flow, the cooling output will

be commanded to:

0% 100%Open

Remain in Control

If the control sensor becomes unreliable, the cooling output is

commanded to:


To Humidification

Section AHUCLG



Should the cooling outputgo to 0% during shutdown?


Should the cooling outputgo to 0% during shutdown?



HardwareAI point

Both withAI backup

Software(N2)

Command

HardwareAI point

Both withAI backup

Position Adjustincremental

Figure 68: Cooling


Select the Type of Cooling Device Choose among the options in Table 47.

Table 47: Select the Type of Cooling Device Option Description None No point/parameter assignment or logic sequence for this

selection. Note: When you select None (no cooling apparatus), HVAC PRO

does not display questions for dehumidification. Modulated Single Coil


Staged See the Key Concepts section for a description of this option. 2-Position Valve w/Face and Bypass


Position Adjust – Incremental


Should the Cooling Command Go to 0% on Shutdown? Choose among the options in Table 48.

Table 48: Should the Cooling Command Go to 0% on Shutdown? Option Description Yes When the Shutdown mode is on, the controlled device will be



Upon Loss of Air Flow, the Cooling Valve will be Commanded To Choose among the options in Table 49.

Table 49: Upon Loss of Air Flow, the Cooling Valve will be Commanded To Option Description 0% Drive the valve to the 0% open position. 100% Drive the valve to the 100% open position. Remain In Control



Is Pump Start Upon Cooling Command Greater Than 0% Needed? Choose among the options in Table 50.

Table 50: Is Pump Start Upon Cooling Command Greater Than 0% Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes The cooling control strategies titled “Modulated Single Coil,”

“Common Heating and Cooling,” and “2-Position Face and Bypass Valve” have the option of an additional output assigned for a pump. This output will be energized when the cooling command is greater than 1%.




Momentary Pulse


Is Outdoor Air Lockout of Cooling Needed? Choose among the options in Table 52.

Table 52: Is Outdoor Air Lockout of Cooling Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes All cooling control strategies may be locked out. The cooling

lockout can be initiated from a controller input, or over the N2 Bus by a FMS.


Select the Method to Initiate Cooling Lockout Choose among the options in Table 53.

Table 53: Select the Method to Initiate Cooling Lockout Option Description Software (N2) Command

A binary data point is provided to initiate the cooling lockout (Figure 69). If communication is lost with the FMS, the controller will maintain the last commanded state for ten minutes. The default of the cooling lockout is off.

Hardware AI Point

An analog input is assigned for an outside air temperature sensor. When the outside air temperature is below the cooling lockout setpoint, the cooling will be locked out; when the outside air temperature is above the setpoint plus the differential, the cooling will be enabled. If the analog input becomes unreliable, the cooling failsoft is enabled.

Both with AI Backup

A binary data point is provided to initiate the cooling lockout. If communication is lost with the FMS, the controller will use the outside air sensor as a backup for the cooling lockout decision. If the analog input becomes unreliable, the cooling failsoft is enabled. In the event N2 communications is lost when the outside air temperature is below the cooling lockout setpoint, the cooling will be locked out; when the outside air temperature is above the setpoint plus the differential, the cooling will be enabled. If the analog input becomes unreliable, the cooling failsoft is enabled.

CoolingLockout

N2 Command


Differential

Compare

CoolingLockout


Differential

Compare


AI Switch

N2 Command Status

N2 Command

CoolingLockout

Command

CLGLOCK

Figure 69: Lockout


If the Control Sensor Becomes Unreliable, the Cooling Valve is Commanded To Choose among the options in Table 54.

Table 54: If the Control Sensor Becomes Unreliable, the Cooling Valve is Commanded To Option Description 0% Drive the valve to the 0% open position. 100% Drive the valve to the 100% open position. Last Reliable Command



Is Vernier Control Needed? (AO Control for % Control Between Stages) Choose among the options in Table 55.

Table 55: Is Vernier Control Needed? (AO Control for % Control Between Stages) Option Description No No point/parameter assignment or logic sequence for this


100% between each stage of cooling. The analog command increases from 0 to 100% as the sequencer cooling command from the control strategy increases from 0 to the starting point of the first stage. When you select Vernier control, the starting point of the first stage defaults to the normal proportional division of the number of stages plus one (i.e., 3 stages would start at 25, 50, and 75% commands). When the sequencer command rises above the first stage on percent, the analog command begins again at 0 and increases to 100% until the sequencer command equals the starting point of the second stage. The analog output operation between each stage is consistent between all stages. The Vernier control strategy cannot be used with rotational sequencing.





started (in order) after the controller turns off the first stage. For example, if Stages 1 - 2 - 3 – 4 energize and then turn off in the opposite order, the next sequence is 2 - 3 - 4 - 1. This new order de-energizes in reverse, and then reorders as 3 - 4 - 1 - 2. When you select the rotational sequencing feature, you cannot use Vernier control.

If the Control Sensor Becomes Unreliable Command Cooling Stages To Choose among the options in Table 57.

Table 57: If the Control Sensor Becomes Unreliable Command Cooling Stages To Option Description 0% Turn all stages off. 100% Turn all stages on. Last Reliable Command

Hold the staged outputs at the last reliable command.

Type of Output Signal (2-Position Valve) Choose among the options in Table 58.

Table 58: Type of Output Signal (2-Position Valve) Option Description Maintained A single binary output is assigned. It will be energized when the

valve is commanded open and de-energized when the valve is commanded closed.

Momentary Pulse

A pair of binary outputs are assigned, the open output will be energized momentarily when the valve is commanded open and the close output will be energized momentarily when the valve is commanded closed. A momentary output has a pulse duration of 1.5 seconds.


Should the Cooling Command Go to 0% on Shutdown? Choose among the options in Table 59.

Table 59: Should the Cooling Command Go to 0% on Shutdown? Option Description Yes When the Shutdown mode is on, the controlled device will be



Upon Loss of Air Flow, the Cooling Face and Bypass Damper will be Commanded To Choose among the options in Table 60.

Table 60: Upon Loss of Air Flow, the Cooling Face and Bypass Damper will be Commanded To Option Description 0% Drive the damper to the 0% face position and turn valve off. 100% Drive the damper to the 100% face position and turn the valve on. Remain In Control


If the Control Sensor Becomes Unreliable, the Cooling Face and Bypass Damper is Commanded To Choose among the options in Table 61.

Table 61: If the Control Sensor Becomes Unreliable, the Cooling Face and Bypass Damper is Commanded To Option Description 0% Drive the damper to the 0% face position and turn valve off. 100% Drive the damper to the 100% face position and turn the valve on. Last Reliable Command

Hold the output at the last reliable position and commands.


Completing the Dehumidification Question/Answer Path To complete the dehumidification question/answer path: 1. Answer the questions as they are presented (Figure 70), using the


2. After the Dehumidification section, the question/answer path continues on to the Humidification section.

Select the dehumidification control strategy

None High signal selectionw/ cooling command

Addition of dehumidificationand cooling command

Select the humiditysensor for dehumidification

To Humidification

Section

Zone Return/Exhaust Air

Is dehumidification needed duringunoccupied mode?

No Yes

If the humidity sensor becomes unreliable, dehumid command =

0% Last reliablecommand

DEHUMID

Figure 70: Dehumidification


Select the Dehumidification Control Strategy Choose among the options in Table 62.

Table 62: Select the Dehumidification Control Strategy Option Description None No point/parameter assignment or logic sequence for this

selection. High Signal Selection w/Cooling Command


Addition of Dehumid. and Cooling Command


Select the Humidity Sensor for Dehumidification Choose among the options in Table 63.

Table 63: Select the Humidity Sensor for Dehumidification Option Description Zone An analog input for a zone humidity sensor is defined. Return/ Exhaust Air

An analog input for a duct insertion return/exhaust air humidity sensor is defined.

Is Dehumidification Needed During Unoccupied Mode? Choose among the options in Table 64.

Table 64: Is Dehumidification Needed During Unoccupied Mode? Option Description No Dehumidification will only be active in the Occupied mode of

operation. Yes When Dehumidification is in use during the Unoccupied mode of

operation, the control output can be commanded above 0% open only during periods of positive supply airflow.


If the Humidity Sensor Becomes Unreliable, Dehumid. Command = Choose among the options in Table 65.

Table 65: If the Humidity Sensor Becomes Unreliable, Dehumid. Command = Option Description 0% Dehumidification command goes to 0%. Last Reliable Command

Hold the command at the last reliable value.


Completing the Humidification Question/Answer Path To complete the humidification question/answer path: 1. Answer the questions as they are presented (Figure 71), using the


2. After the Humidification section, the question/answer path continues on to the Modes of Operation section.

None

To Modes ofOperation

Section

Select humidification control strategy:

Staged Modulated

SEQUENCER: Number of stages

One through Nine

Select the setpoint type

Single humidificationsetpoint

% RH setpoint resetby outdoor air temp.

Select the humidity sensor for humidification

Zone Return/Exhaust air

Is humidification needed duringunoccupied mode?

No Yes

HUMID

Figure 71: Humidification


Select the Humidification Control Strategy Choose among the options in Table 66.

Table 66: Select the Humidification Control Strategy Option Description None No point/parameter assignment or logic sequence for this

selection. Staged As the control humidity decreases below the user defined setpoint

and into the humidification proportional band, the controller calculates a 0 to 100% command. Staged humidification requires parameter inputs for cycle, interstage, and minimum on/off timers. Vernier and rotational sequencing is not available for staged humidification outputs. Adding integration to a control loop with staged outputs is not advised, as it usually results in the constant cycling of the outputs.

Modulated The system controls the modulated humidity (i.e., steam) coil based on the provided humidity sensor (Figure 72). As the control humidity decreases below the user defined setpoint and into the humidification proportional band, the controller issues a 0 to 100% command to the humidification device. During PI control, if the humidity sensor value is within the deadband area, the error is considered 0 and the control output holds constant. In proportional only control, if the sensor value is within the deadband area, the output command is 0%.

ABO6

Purge Vent

Shutdown

FailSoft

Humidity AIHumidification Setpoint

Proportional BandIntegrationDeadband

Offset

PI Control

Outdoor Temperature AI Outdoor Low Limit

Outdoor Reset BandHumidification Low Limit

Humidification Reset Band

Humidity Reset

HumidityIntegration

AO0

0

0 0

1 orOccupied

12

12

0

Shutdown

0

0

AND

Supply AirflowSupply Fan

Figure 72: Modulated Humidification Reset from Outside Air Temperature



Select the Setpoint Type Choose among the options in Table 67.

Table 67: Select the Setpoint Type Option Description Single Humidification Setpoint

A single humidification setpoint is used for humidification control. The value entered for the humidity deadband is active equally above and below the setpoint.

% RH Setpoint Reset by Outdoor Air Temp.

The outdoor air reset schedule performs a direct readjustment of the humidification setpoint. As the outdoor air temperature decreases, the humidification setpoint also decreases. The reset schedule is configured through the humidity low limit and reset band. It is associated with the outdoor air low limit and reset band.

Select the Humidity Sensor for Humidification Choose among the options in Table 68.

Table 68: Select the Humidity Sensor for Humidification Option Description Zone An analog input for a zone humidity sensor is defined. Return/ Exhaust Air

An analog input for a duct insertion return/exhaust air humidity sensor is defined.

Is Humidification Needed During Unoccupied Mode? Choose among the options in Table 69.

Table 69: Is Humidification Needed During Unoccupied Mode? Option Description No Humidification will only be active in the Occupied mode of

operation. Yes When humidification is in use during the Unoccupied mode of

operation, the control output can be commanded above 0% open only during periods of positive supply airflow.

Completing the Modes of Operation Question/Answer Path To complete the modes of operation question/answer path: 1. Answer the questions as they are presented (Figure 73), using the


2. After the Modes of Operation section, the question/answer path continues on to the Fan System Control section.


Select the unoccupied control strategy:

None Intermittent night operation from zone

Select the method to control the occupied/unoccupied mode of operation:

Software(N2) command

Hardware BI point

Both withBI backup

Both can activate

Should a default occ/unocc schedule

take effect when the N2 is disconnected?

No Yes

How is shutdown mode initiated?

Should a default shutdown schedule

take effect when the N2 is

disconnected?

No Yes

Setup/setbackof htg/clg setpts

in main seqoperation from zone*

* only in room

controlstrategy

How is warmup/cooldown initiated?

No warmup/cooldown needed

Power fail restart logic?

No Yes

UNOCC

To Fan System

ControlSection

How is shutdown mode initiated?

Should a default shutdown schedule

take affect when the N2 is

disconnected?

No Yes


Hardware BI point

Both withBI backup

Both can activate


Hardware BI point

Both withBI backup

Both can activate


Hardware BI point

Both withBI backup

Both can activate

Figure 73: Modes of Operation


Select the Unoccupied Control Strategy Choose among the options in Table 70.

Table 70: Select the Unoccupied Control Strategy Option Description None No point/parameter assignment or logic sequence for

this selection. The controller always operates in Occupied mode and only shuts down through Shutdown mode. HVAC PRO does not display questions for warmup/cooldown since this is an unoccupied feature.

Intermittent Night Operation from Zone Sensor


Setup/Setback of Htg/Clg Setpts in Main Seq Operation from Zone (Only in Room Control Strategy)



Select the Method to Control the Occupied/Unoccupied Mode of Operation Choose among the options in Table 71.

Table 71: Select the Method to Control the Occupied/Unoccupied Mode of Operation Option Description Software (N2) Command

An occupied binary data point is provided for a facility management system to command. A default/backup time schedule in the controller takes effect when loss of communication with a supervisory device occurs. The time schedule follows occupied start and stop time parameters based on the controller’s internal clock. The controller’s clock is not battery backed and will reset to 00:00 hours whenever the controller resets, such as occurs after a power failure. Only a supervisory device (Companion/Facilitator, NCM, or ZT) can set the controller’s clock. When both start and stop time parameters are set to the same value, occupied remains on in standalone. If the backup schedule is not used and communication loss with a supervisory device occurs, the controller will maintain the last commanded state for ten minutes and then default the Occupied mode as on.

Hardware BI Point

A hardware binary input is provided to switch the controller between Occupied and Unoccupied modes. When the contact is closed, occupied status is on.

Both with BI Backup

An occupied binary data point is provided for a facility management system to command. If communication with the FMS is lost, the status of the binary input is used to determine Occupied mode.

Both can Activate

An occupied binary data point is provided for a facility management system to command. A hardware binary input is also provided to switch the controller between Occupied and Unoccupied modes. Either point can place the controller into the Occupied mode. Both points must be off for the controller to be in the Unoccupied mode.


How is Shutdown Mode Initiated? Choose among the options in Table 72.

Table 72: How is Shutdown Mode Initiated? Option Description Software (N2) Command

A shutdown binary data point is provided for a facility management system to command. If the backup schedule is not used and communication loss with a supervisory device occurs, the controller will maintain the last commanded state for ten minutes and then default to Occupied mode as on.

Hardware BI Point

A hardware binary input is provided to switch the controller into the Shutdown mode. When the contact is closed, the Shutdown mode is on.

Both with BI Backup

A shutdown binary data point is provided for a facility management system to command and a hardware binary input is provided for backup. If communication with the FMS is lost, the status of the binary input is used to determine Shutdown mode.

Both can Activate

A shutdown binary data point is provided for a facility management system to command. A hardware binary input is also provided to switch the controller into Shutdown mode. Either point can place the controller into the Shutdown mode. Both points must be off for the controller to turn Shutdown mode off. When shutdown is enabled, all outputs to fans are turned off and the economizer dampers are closed. Preheat, heating, and cooling outputs will be shutdown to 0% command if the user specified they be affected by shutdown. Otherwise, they will go to their “loss of airflow position”. In Shutdown mode, all integration timers are set to 0, so no windup occurs when the system is put back into control.


Should a Default Shutdown Schedule Take Effect When the N2 is Disconnected? Choose among the options in Table 73.

Table 73: Should a Default Shutdown Schedule Take Effect When the N2 is Disconnected? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes A default/backup time schedule in the controller takes effect when

loss of communication with a supervisory device occurs. The time schedule follows shutdown start and stop time parameters based on the controller’s internal clock. The controller’s clock is not battery backed and will reset to 00:00 hours whenever the controller resets, such as occurs after a power failure. Only a supervisory device (Companion/Facilitator, NCM, or ZT) can set the controller’s clock. When both start and stop time parameters are set to the same value, shutdown remains on in standalone. If the backup schedule is not used and communication loss with a supervisory device occurs, the controller will maintain the last commanded state for ten minutes and then default the Shutdown mode as off.

How is Warmup/Cooldown Initiated? Choose among the options in Table 74.

Table 74: How is Warmup/Cooldown Initiated? Option Description No Warmup/Cooldown Mode Needed

No point/parameter assignment or logic sequence for this selection.


A warmup/cooldown binary data point is provided for a facility management system to command. If communication is lost with the FMS, the controller will maintain the last commanded state for ten minutes. The default of the Warmup/Cooldown mode is off.

Hardware BI Point

A hardware binary input is provided to switch the controller into the Warmup/Cooldown mode. When the contact is closed, the Warmup/Cooldown mode is on.

Both with BI Backup

A warmup/cooldown binary data point is provided for a facility management system to command and a hardware binary input is provided for backup. If communication with the FMS is lost, the status of the binary input is used to determine warmup/cooldown mode.

Both can Activate

A warmup/cooldown binary data point is provided for a facility management system to command. A hardware binary input is also provided to switch the controller into Warmup/Cooldown mode. Either point can place the controller into the Warmup/Cooldown mode. Both points must be off for the controller to turn Warmup/Cooldown mode off.


Power Fail Restart Logic?

ShutdownCommand

Shutdown

ORNOT

B010B

DelayOnRestart Delay Time

Controller Reset Trigger

Figure 74: Power Fail Restart Choose among the options in Table 75.

Table 75: Power Fail Restart Logic? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes A power fail restart delay time delays the startup of the unit after a

power failure or controller reset condition. This logic holds the controller in Shutdown mode until the restart timer expires. This strategy prevents the startup of multiple controllers upon the restoration of power. When power is restored to the controller, the reset trigger is initially equal to 0. This results in shutdown being on. When reset completes, the reset trigger is equal to on. This causes a delay before shutdown is commanded back to off.

Completing the Fan System Control Question/Answer Path To complete the fan system control question/answer path: 1. Answer the questions as they are presented (Figure 75), using the


2. The Fan System Control section is the final portion of the question/answer path. You have completed the AHU applications question and answer path.


Select the fan system control type:

Single Supply fan, w/static press cntl

Single sup/ret vol match w/stat pres ctl

Single supply, low/high speed

control

Constant volume

Is low static selection between

two sensors needed?

No Yes

Is ramp control upon supply fan startup needed?

No Yes

Is supply flow needed from an air flow measuring

station?

No Yes

Select the type of air flow

measurement:

Pitot tube

Scaled input-air flow station thermistor

Should the supply/return fan be commanded "OFF" upon a loss of air flow?

No Yes

Maintained Momentary Pulse

Type of output signal (supply) :

Is an alternate flow differential setpoint required for unocc'd or warmup modes?

No Yes

Is low static selection between

two sensors needed?

No Yes

Is ramp control upon supply fan startup needed?

No Yes

Is supply flow needed from an air flow measuring

station?

No Yes

Select the type of air flow

measurement:

Pitot tube

Scaled input-air flow station thermistor

FANSYSE

Figure 75: Fan System Control


Will the controller start and stop the return fan?

No Yes

Select which fan should start first:

Supply Return

Type of output signal (return) :

Maintained Momentary Pulse

DONE

E

FANSYS

Figure 76: Fan System Control (Cont.)

Select the Fan System Control Type Choose among the options in Table 76.

Table 76: Select the Fan System Control Type Option Description Single Supply Fan with Static Press. Cntl


Single Sup/Ret Vol Match w/Static Press Cntl


Single Supply, Low/High Speed Control


Constant Volume See the Key Concepts section for a description of this option.


Is Low Static Selection Between Two Sensors Needed? Choose among the options in Table 77.

Table 77: Is Low Static Selection Between Two Sensors Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes Two static pressure sensors can be selected for the AHU

controller configuration. The lowest static pressure value is in use as the input to the static pressure PID control loop.

Is Ramp Control Upon Supply Fan Startup Needed? Choose among the options in Table 78.

Table 78: Is Ramp Control Upon Supply Fan Startup Needed? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes A ramp step, in percent per second, is a user adjustable

parameter. When the static pressure setpoint is obtained during the ramp routine, the PID loop internal integration value will be set equal to the ramp signal offset and the ramp will end. This will provide a smooth transition from the ramp routine to PID control. For example, to achieve 30% command in ten minutes calculate the ramp step as follows: 10 min x 60 secs = 600 seconds 30% ÷ 600 secs = 0.05% per second, so the ramp step is 0.05% Note: If the fan status is not on by the time the step reaches

setpoint, the fan output will go to 0% and the ramp will restart.


WITHRAMP

0

0

Static Pressure

StaticIntegrationTerm

FailSoft

0

MINSelect

Static Pressure 1Static Pressure 2

Supply Fan Cmd

ORDelayOFF

SupplyAirflow

Stored Integration

ANDCOMPARE>

Static Setpoint

Ramp Status

RAMP0

Supply Ramp Step

SUBStatic Offset

Ramp



OffsetDeadband

AOSupply FanControl

Figure 77: Single Supply Fan, Static Pressure, with Ramp Control

RFMSSFRN

0

0

ReturnVolumeIntegrationTerm

FailSoft

0

Return Fan Cmd

ORDelayOFFReturn Airflow

CFMCalculation

Supply VolumeVelocity Pressure SUB

Return Fan Offset

Supply Ramp StatusON = Ramping

When supply fan ramp is chosen:

When supply fan ramp is not chosen:

XORDelayON

Return FanCommand

Unocc CFM Differential

Occupancy

Occ CFM Differential



OffsetDeadband

AOReturn FanControl

CFMCalculation

Return Volume Velocity Pressure

Duct Area

Duct Area

Figure 78: Single Supply/Return Fan, Volume Matching, with Ramp Control


Is Supply Flow Needed from an Air Flow Measuring Station? Choose among the options in Table 79.

Table 79: Is Supply Flow Needed from an Air Flow Measuring Station? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes Supply airflow in CFM is calculated for monitoring purposes only.

Select the Type of Air Flow Measurement Choose among the options in Table 80.

Table 80: Select the Type of Air Flow Measurement Option Description Pitot Tube This selection is required when the controller needs to calculate

the square root of the velocity pressure reading. The area of the face of the airflow station is required, and a constant is required to extract any amplification of the velocity pressure that is present in the design of the Pitot tube traverse. The formula for the CFM calculation of the Pitot tube method is shown in Figure 79.

Airflow Station (Thermistor)

This selection is intended for a packaged airflow station having a linear output ranged in velocity (FPM) or volume (CFM). In cases where the airflow station outputs a linear CFM signal, adjust the value for the area of the airflow measuring station to 1.0. CFM = (V)(A) Where: V = velocity (ft/min) A = area of the airflow station (sq ft)

BO11A

Supply Velocity PressureDuct AreaConstant

CFMCALC

CFM

CFM = (4005) (Pv/K) (A) Where: Pv = velocity pressure (in. WG)

K = constant (provided by the device manufacturer)A = area of the airflow station (sq ft)

MULTIPLY CFM

BO11B

Velocity(ft/min)

Duct Area

Figure 79: CFM Calculations


Is an Alternate Flow Differential Setpoint Required for Unocc’d or Warmup Modes? Choose among the options in Table 81.

Table 81: Is an Alternate Flow Differential Setpoint Required for Unocc’d of Warmup Modes? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes The CFM differential can be adjusted to a different value

(typically 0) for unoccupied operation.

Type of Output Signal (Supply) Choose among the options in Table 82.

Table 82: Type of Output Signal (Supply) Option Description Maintained A single binary output is assigned. It will be energized when the

fan command is on and de-energized when the fan command is off.

Momentary Pulse

A pair of binary outputs are assigned. The start output will be energized momentarily when the fan command is on and the stop output will be energized momentarily when the fan command is off. A momentary output has a pulse duration of 1.5 seconds.

Should the Supply/Return Fan be Commanded “OFF” Upon a Loss of Air Flow? Choose among the options in Table 83.

Table 83: Should the Supply/Return Fan be Commanded “OFF” Upon a Loss of Air Flow? Option Description No If airflow interlock is selected and airflow is lost, the controller will

leave the fan command on and will still give airflow status indication and airflow failure alarm.

Yes When airflow is lost, after a user adjustable delay, the fan alarm will go on and the fan command will be turned off. The occupied or Warmup/Cooldown mode must toggle on, or the shutdown must toggle off to trigger another start command to the fan. Also, if the airflow status is toggled on, a start command will be issued and the fan alarm will clear.


Will the Controller Start and Stop the Return Fan? Choose among the options in Table 84.

Table 84: Will the Controller Start and Stop the Return Fan? Option Description No No point/parameter assignment or logic sequence for this

selection. Yes The controller will start and stop the return fan in sequence with

the supply fan. A user-adjustable fan delay time is loaded in the supply fan parameters list. This is the time between the start commands of the supply fan and the return fan.

Type of Output Signal (Return) Choose among the options in Table 85.

Table 85: Type of Output Signal (Return) Option Description Maintained A single binary output is assigned. It will be energized when the

fan command is on and de-energized when the fan command is off. Supply fan airflow status triggers the start and stop commands to the return fan.

Momentary Pulse

A pair of binary outputs are assigned. The start output will be energized momentarily when the fan command is on and the stop output will be energized momentary when the fan command is off. A momentary output has a pulse duration of 1.5 seconds. Supply fan airflow status triggers the start and stop commands to the return fan.

Select Which Fan Should Start First Choose among the options in Table 86.

Table 86: Select Which Fan Should Start First Option Description Supply or Return

When selecting the supply and return fan start/stop, the user can select if the return or the supply fan will start first. It may be necessary to start the return fan first. This strategy could prevent damage to ductwork, or avoid a low temperature switch from dropping out the supply fan starter circuit due to excessively low ambient outside air during startup by pressurizing the mixed air temperature plenum with warmer return air.


Troubleshooting Downloading an AHU Application

The following concerns problems that may be encountered when downloading an AHU assembled at HVAC PRO Release 4.00 or 5.00. Note: This overflow is only likely to occur on a very limited

number of jobs. Do not let this hamper the upgrade of your AHU jobs to HVAC PRO Release 5.00.

Table 87: Troubleshooting AHU Controllers Error/Condition Problem Solution Large Configurations Overflow the Amount of Configuration Space in the AHU Memory

Due to the enhancements/improvements made in the AHU paths since HVAC PRO Release 3.0, some large configurations may overflow the amount of configuration space in the AHU memory. The problem affects AHU revisions C05 or earlier. The user will not be informed that the program is too large, and the following symptoms can occur: • The AHU, after the download,

resets continually. • The Binary Inputs no longer

update their actual condition.

If you experience one of the symptoms described in the Problem column after downloading the AHU, perform the following: 1. Download the file AHU500.EXE from the Main

Board of the Bulletin Board System. This file is self-extracting and will give you

three files: AHUASM.EXE, FIXRESET.EXE and README.TXT.

2. Perform the steps in the README file to fix the reset problem.

3. Download the AHU with your original program created with an earlier release of HVAC PRO.

If you are upgrading your AHU programs or configuring a new AHU with HVAC PRO Release 5.00, perform the following: 1. Download the file AHU500.EXE from the Main

Board of the Bulletin Board System. This file is self-extracting and will give you

three files: AHUASM.EXE, FIXRESET.EXE and README.TXT.

2. Assemble your AHU configuration with HVAC PRO Release 5.0.

This new assembler will generate an error message Configuration Data Overflow if the file you are assembling will overflow the AHU memory. The object code necessary for download will not be created.

3. If your AHU configuration generates this message, re-configure and download at HVAC PRO Release 3.03.


Saving an AHU Application File for a UNT Controller When using the Save As command to save a configuration to a different target device, all available devices should appear in the Devices window. If the Devices window reads No Target Device, look in the Reason Not Allowed: at the bottom of the screen for the reason. The most common reasons are provided below, along with suggested solutions for these issues. No Target Device is a valid option to save a configuration temporarily until you decide which option is best for your application. Note: It is not possible to load a UNT application into an AHU or

VAV (Variable Air Volume controller). It is not possible to load an AHU application into a VAV.

Table 88: Reasons for No Target Device Message Reason Solutions The device UNT1nn-n does not have enough AIs.

• Move the AIs up into the first six AIs if possible.

• Eliminate a feature that uses an AI. The device UNT1nn-n does not have enough AOs.

• Move the voltage AOs up into the first two AOs.

• Change the AO device type to a Zone Bus, and move it to AO-3 or greater.

The device UNT1nn-n does not have enough BIs.

Eliminate a feature that uses a BI.

The device UNT1nn-n does not support one of the AI sensors.

Change AI sensor types to Resistive or Voltage.

The device UNT1nn-n does not support one of the AO types.

Change AO device types to Voltage, Pneumatic, or Zone Bus.


Point Assignments and Parameters Default Point Assignments

Table 89 provides the default point assignments for AHU applications.

Table 89: AHU Application Default Point Assignments Point Type Point Index Point Name AI 1st available Glycol Temp AI 1st available Heat Recov Temp AI 1st available Htg/Clg Sensor AI 1st available Minpos Vel Press AI 1st available OA Rel Humid AI 1st available Return Vel Press AI 1st available Return Velocity AI 1st available Supply Velocity AI 1 Outdoor Air Temp AI 2 Mixed Air Temp AI 3 Disch Air Temp AI 3 Hot Deck Temp AI 4 Cold Deck Temp AI 4 Zone Temp AI 5 Exhaust Temp AI 5 Minpos Velocity AI 5 Return Air Temp AI 6 Preheat Control AI 7 Coldest Zone AI 7 Rem Clg Setpoint AI 7 Static Press AI 7 Static Press #1 AI 7 Zone Rel Humid AI 8 Air Quality AI 8 Rem Htg Setpoint AI 8 Rem Zone Setpnt AI 8 Return Rel Humid AI 8 Static Press #2 AI 8 Supply Vel Press AI 8 Warmest Zone Continued on next page . . .


Point Type (Cont.)

Point Index Point Name

BI 1st available Purge BI 1st available Return Airflow BI 1st available Supply Airflow BI 1st available Vent BI 2 Econ Switch BI 2 Occupied BI 2 Warmup/Cooldown BI 2 Summer/Winter BI 3 Shutdown AO 1st available Clg Face/Bypass AO 1st available Cooling Valve AO 1st available Cooling Vernier AO 1st available Heating Valve AO 1st available Heating Vernier AO 1st available Ht Recov Valve AO 1st available Htg Face/Bypass AO 1st available Htg/Clg Valve AO 1st available Humid Valve AO 1st available Min Damper Cmd AO 1st available Preheat Valve AO 1st available Preheat Vernier AO 1st available Preht Face/Bypass AO 1st available Return Fan Cntl AO 1st available Supply Fan Cntl AO 1 Damper Command AO 5 Humid Command AO 6 Preheat Command AO 7 Heating Command AO 8 Cooling Command AO 8 Preheat Control Continued on next page . . .


Point Type (Cont.)


BO 1st available Cooling Pump BO 1st available Cooling Pump BO 1st available Cooling Pump Off BO 1st available Cooling Stage 1 BO 1st available Cooling Stage 2 BO 1st available Cooling Stage 3 BO 1st available Cooling Stage 4 BO 1st available Cooling Stage 5 BO 1st available Cooling Stage 6 BO 1st available Cooling Stage 7 BO 1st available Cooling Stage 8 BO 1st available Cooling Stage 9 BO 1st available Cooling Valve BO 1st available Cooling Valve BO 1st available Cooling Valve Off BO 1st available Heating Pump BO 1st available Heating Pump BO 1st available Heating Pump Off BO 1st available Heating Stage 1 BO 1st available Heating Stage 2 BO 1st available Heating Stage 3 BO 1st available Heating Stage 4 BO 1st available Heating Stage 5 BO 1st available Heating Stage 6 BO 1st available Heating Stage 7 BO 1st available Heating Stage 8 BO 1st available Heating Stage 9 BO 1st available Heating Valve BO 1st available Heating Valve BO 1st available Heating Valve Off BO 1st available Ht Recov Pump BO 1st available Ht Recov Pump BO 1st available Ht Recov PumpOff BO 1st available Ht Recov Valve BO 1st available Htg Face/Bypass Continued on next page . . .


Point Type (Cont.)


BO 1st available Htg Face/Bypass BO 1st available Humid Stage 1 BO 1st available Humid Stage 2 BO 1st available Humid Stage 3 BO 1st available Humid Stage 4 BO 1st available Humid Stage 5 BO 1st available Humid Stage 6 BO 1st available Humid Stage 7 BO 1st available Humid Stage 8 BO 1st available Humid Stage 9 BO 1st available Min Damper Cmd BO 1st available Preheat Pump BO 1st available Preheat Pump BO 1st available Preheat Pump Off BO 1st available Preheat Stage 1 BO 1st available Preheat Stage 2 BO 1st available Preheat Stage 3 BO 1st available Preheat Stage 4 BO 1st available Preheat Stage 5 BO 1st available Preheat Stage 6 BO 1st available Preheat Stage 7 BO 1st available Preheat Stage 8 BO 1st available Preheat Stage 9 BO 1st available Preheat Valve BO 1st available Return Fan BO 1st available Return Fan BO 1st available Return Fan Off BO 1st available Supfan HI Off BO 1st available Supfan HI Speed BO 1st available Supfan HI Speed BO 1st available Supfan LO Off BO 1st available Supfan LO Speed BO 1st available Supfan LO Speed BO 1st available Supply Fan BO 1st available Supply Fan BO 1st available Supply Fan Off


Default Parameters Table 90 provides the default parameters for AHU applications. Note: Values in parentheses are metric defaults.

Table 90: AHU Application Default Parameters Parameter Point

Location Default Value Description

Actual Cold Deck Setpt

ADF 18 calculated variable Actual cold deck setpoint being used

Actual Disch Clg Setpt ADF 18 calculated variable Actual discharge air cooling setpoint being used

Actual Disch Htg Setpt ADF 17 calculated variable Actual discharge air heating setpoint being used

Actual Disch Setpt ADF 17 calculated variable Actual discharge air setpoint being used Actual Hot Deck Setpt ADF 17 calculated variable Actual hot deck setpoint being used Actual Humid Setpt ADF 23 calculated variable Actual humidity setpoint Actual Mxd Air Setpnt ADF 24 calculated variable Actual mixed air setpoint Alt Clg Deadband ADF 146 0.0°C (0.0°F) Alternate cooling deadband when damper is

closed Cld Deck Low Lim ADF 144 12.0°C (55.0°F) Cold Deck Reset - cold deck low limit setpoint Cld Deck RBand ADF 145 11.0°C (20.0°F) Cold Deck Reset - cold deck reset band Cld Zone Hi Lim ADF 138 22.0°C (72.0°F) Hot Deck Reset - coldest zone low limit

setpoint Cld Zone RBand ADF 139 -2.0°C (-4.0°F) Hot Deck Reset - coldest zone reset band Clg % Stage 1 SP ADI 227 0.0% Percent command required for the first stage

to turn on Clg 2 Pos SP ADF 179 1% (1%) 2-position cooling valve setpoint Clg Lockout Cmd BD 205 0 = Off Cooling lockout command Clg Lockout Stat BD 22 0 = Off Cooling lockout status Clg OA Diff ADF 178 1.5°C (3.0°F) Cooling lockout OA differential Clg OA Setpoint ADF 177 12.0°C (55.0°F) Cooling lockout OA setpoint Coast Time ADF 252 10.0 Secute

(10.0 Sec) Coast time for two speed fan

Cold Deck DBand ADF 136 28.0°C (50.0°F) Deadband for the cold deck temperature loop Cold Deck Int Tm ADF 132 60 Integration time for the cold deck temperature

loop Cold Deck PBand ADF 137 16.0°C (30.0°F) Proportional band for the cold deck

temperature loop Cooling Command AO 8 Calculated value Cooling command Cooling Setpoint ADF 130 22.0°C (72.0°F) Zone Control - cooling setpoint Damper Duct Area ADF 157 0.4 sq m (4.0 sq ft) Minimum damper duct area for flow

calculation Damper Flow Mult ADF 158 1.00 Minimum damper flow constant for flow

calculation Deck Econ PBand ADF 133 28.0°C (50.0°F) Proportional band for the cold deck

economizer loop Continued on next page . . .


Parameter (Cont.)

Point Location

Default Value Description

Default Econ SP ADF 150 20.0°C (68.0°F) Economizer switchover default OA dry bulb setpoint

Dehumid DBand ADF 182 0.0% RH Controller deadband for dehumidification loop Dehumid Int Tm ADF 181 0 Integration term for dehumidification loop Dehumid Offset ADF 184 0.0% RH Controller bias for dehumidification loop Dehumid PBand ADF 183 10.0% RH Proportional band for dehumidification loop Dehumid Setpoint ADF 180 50.0% RH Dehumidification setpoint Disch Clg DBand ADF 136 28.0°C (50.0°F) Deadband for the discharge cooling

temperature loop Disch Clg Int Tm ADF 139 60 Integration time for the discharge cooling loop Disch Clg LowLim ADF 142 12.0°C (55.0°F) Supply Air Reset - discharge cooling low

setpoint Disch Clg PBand ADF 141 16.0°C (30.0°F) Proportional band for the discharge cooling

temperature loop Disch Clg RBand ADF 143 11.0°C (20.0°F) Supply Air Reset - discharge cooling reset

band Disch Econ PBand ADF 133 28.0°C (50.0°F) Proportional band for the discharge

economizer loop Disch Htg DBand ADF 134 1.0°C (2.0°F) Deadband for the discharge heating

temperature loop Disch Htg DBand ADF 133 0.0°C (0.0°F) Heating deadband for constant discharge

temperature loop Disch Htg Int Tm ADF 138 60 Integration time for the discharge heating

loop Disch Htg LowLim ADF 144 24.0°C (75.0°F) Supply Air Reset - discharge heating low

setpoint Disch Htg LowLim ADF 144 12.0°C (55.0°F) Room Reset of Heating - discharge heating

low setpoint Disch Htg PBand ADF 140 33°C (60°F) Proportional band for the discharge heating

temperature loop Disch Htg RBand ADF 145 11.0°C (20.0°F) Supply Air Reset - discharge heating reset

band Disch Htg RBand ADF 145 22.0°C (40.0°F) Room Reset of Heating - discharge heating

reset band Disch Low Limit ADF 142 12.0°C (55.0°F) Supply Air Reset - discharge low setpoint Disch Reset Band ADF 143 22.0°C (40.0°F) Supply Air Reset - discharge reset band Discharge Setpnt ADF 129 42.0°C (60.0°F) Discharge air control - discharge setpoint Econ Status BD 19 0 = Off Economizer status ON = outdoor air cooling

available Econ Switch BD 199 0 = Off Economizer switchover command Econ Switch Diff ADF 151 1.0°C (2.0°F) Economizer switchover OA dry bulb

differential Econ Switch SP ADF 150 20.0°C (68.0°F) Economizer switchover OA dry bulb setpoint Enthalpy Diff SP ADF 151 0.5 KCl/Kg

(1.0 Btu/lb) Economizer switchover enthalpy differential

Exhaust Setpoint ADF 129 24.0°C (75.0°F) Exhaust Control - exhaust setpoint Continued on next page . . .


Parameter (Cont.)

Point Location


Exhst Clg Int Tm ADF 132 600 Integration time for the exhaust cooling temperature loop

Exhst Clg PBand ADF 137 8°C (15°F) Proportional band for the exhaust cooling temperature loop

Exhst Htg DBand ADF 134 0.5°C (1.0°F) Deadband for the exhaust heating temperature loop

Exhst Htg Int Tm ADF 131 600 Integration time for the exhaust heating temperature loop

Exhst Htg PBand ADF 135 -11°C (-20°F) Proportional band for the exhaust heating temperature loop

Fan Delay ADF 253 0.5 Minute Fan delay time Glycol Low Lim ADF 155 3.5°C (38.0°F) Heat Recovery - glycol low limit setpoint Glycol PBand ADF 156 22°C (40°F) Heat Recovery - glycol low limit prop band Glycol DBand ADF 153 0.0°C (0.0°F) Heat Recovery - glycol low limit deadband Glycol Int Tm ADF 154 90 Heat Recovery - glycol low limit integr. time Heating Command AO 8 Calculated value Heating command Heating Setpoint ADF 129 21.5°C (71.0°F) Zone Control - heating setpoint Hot Deck Int Tm ADF 131 60 Integration time for the hot deck temperature

control Hot Deck Low Lim ADF 140 24.0°C (75.0°F) Hot Deck Reset - hot deck low limit setpoint Hot Deck PBand ADF 135 -33°C (-60°F) Proportional band for hot deck temperature

control Hot Deck RBand ADF 141 11.0°C (20.0°F) Hot Deck Reset - hot deck reset band Hot Zone Hi Lim ADF 142 25.5°C (78.0°F) Cold Deck Reset - hottest zone high limit

setpoint Hot Zone RBand ADF 143 3.5°C (-6.0°F) Cold Deck Reset - hottest zone reset band Ht Recov DBand ADF 154 0.0°C (0.0°F) Controller deadband for the heat recovery

temperature loop Ht Recov Diff ADF 151 2.5°C (5.0°F) Heat recovery differential Ht Recov Int Tm ADF 152 90 Integration time for the heat recovery

temperature loop Ht Recov Offset ADF 153 0.0% Controller bias for the heat recovery

temperature loop Ht Recov PBand ADF 151 -22°C (-40°F) Proportional band for the heat recovery

temperature loop Ht Recov Setpnt ADF 150 1.5°C (35.0°F) Heat recovery ON setpoint Ht Recov Setpnt ADF 150 10.0°C (50.0°F) Heat recovery temperature loop setpoint Htg % Stage 1 SP ADI 226 0.0% Percent command required for the first stage

to turn on Htg 2 Pos SP ADF 175 1% 2-position heating valve setpoint Htg High Setpnt ADF 175 38.0°C (100.0°F) Summer winter switchover setpoint Htg High SP Diff ADF 176 22.0°C (40.0°F) Summer winter switchover differential Htg Lockout Cmd BD 204 0 = Off Heating lockout command Htg Lockout Stat BD 21 0 = Off Heating lockout status Htg OA Diff ADF 174 1.5°C (3.0°F) Heating lockout OA differential Continued on next page . . .


Parameter (Cont.)

Point Location


Htg OA Setpoint ADF 173 12.0°C (55.0°F) Heating lockout OA setpoint Humid Command AO 8 Calculated value Humidity command Humid Deadband ADF 187 0.0% RH Controller deadband for humidification loop Humid Int Tm ADF 186 0 Integration term for humidification loop Humid Low Lim SP ADF 190 20.0% RH Humidification low humidity setpoint Humid OA Low SP ADF 192 -23.0°C (-10.0°F) Humidification low OA setpoint Humid OA RBand ADF 193 22.0°C (40.0°F) Humidification OA reset band Humid Offset ADF 189 0.0% RH Controller bias for humidification loop Humid Prop Band ADF 188 -10.0% RH

(-10.0% RH) Proportional band for humidification loop

Humid Reset Band ADF 191 20.0% RH Humidification humidity reset band Humid Setpoint ADF 185 40.0% RH Humidity setpoint IAQ Low Limit ADF 153 800 ppm (800 ppm) Indoor air quality low limit setpoint IAQ Reset Band ADF 154 200 ppm (200 ppm) Indoor air quality reset band Indoor Air Quality ADF 21 Calculated value Indoor air quality actual setpoint Min Pos DBand ADF 160 0.0% Controller deadband for minimum flow loop Min Pos Int Tm ADF 159 20 Integration time for minimum flow loop Min Pos Offset ADF 162 0.0% Controller bias for minimum flow loop Min Pos PBand ADF 161 -140000 L/M

(-5000 CFM) Proportional control for minimum flow loop

Min Pos RBand ADF 155 10.0% (10.0%) Minimum position reset band Min Pos RBand ADF 155 28000 L/M

(1000.0 CFM) Minimum position reset band

Minduct_flow ADF 22 Calculated variable Minimum damper actual flow Minimum Pos ADF 156 57000 L/M

(2000 CFM) Minimum position setpoint

Minimum Pos ADF 156 15.0% Minimum damper minimum position setpoint Mxd Air Deadband ADF 244 0.0°C (0.0°F) Deadband for the mixed air loop Mxd Air Int Tm ADF 243 100 Integration term for mixed air control Mxd Air LL DBand ADF 242 0.0°C (0.0°F) Deadband for the mixed air low limit loop Mxd Air LL Int Tm ADF 241 80 Integration time for mixed air low limit Mxd Air LL Offst ADF 165 0.0°C (0.0°F) Minimum damper position for mixed air low

limit Mxd Air LL PBand ADF 164 -16.5°C (-30°F) Proportional band for the mixed air low limit

loop Mxd Air Low Lim ADF 163 7.0°C (45.0°F) Mixed air low temperature limit Mxd Air Propband ADF 245 33.0°C (50.0°F) Proportional band for the mixed air loop Mxd Air Setpoint ADF 246 13.0°C (55.0°F) Mixed air setpoint Night Clg Diff ADF 197 2.5°C (5.0°F) Unoccupied cooling differential Night Clg Setpnt ADF 196 27.5°C (82.0°F) Unoccupied cooling setpoint Night Htg Diff ADF 195 2.5°C (5.0°F) Unoccupied heating differential Night Htg Setpnt ADF 194 15.5°C (60.0°F) Unoccupied heating setpoint Continued on next page . . .


Parameter (Cont.)

Point Location


OA Enthalpy ADF 19 0.0 KCl/kg (0.0 Btu/lb)

Calculated outdoor air enthalpy

OA Enthalpy Diff ADF 152 0.5 KCl/kg (1.0 Btu/lb)

Economizer switchover OA enthalpy differential

OA Enthalpy SP ADF 151 14.0 KCl/Kg (25.0 Btu/lb)

Economizer switchover OA enthalpy setpoint

Occ Flow Diff ADF 215 57000 L/M (2000 CFM)

Occupied flow differential

Occ Start Time ADI 136 00:00 Hr:Mn Occupied start time Occ Stop Time ADI 137 00:00 Hr:Mn Occupied stop time Occupied Command BD 196 1 = Occ Occupied command. 0 = Unoccupied. Occupied Status BD 27 1 = Occ Occupied mode status. 0 = Unoccupied. Preheat Command AO 8 Calculated value Preheat command Preht % Stage 1 SP ADI 225 0.0% Percent command required for the first stage

to turn on Preht Deadband ADF 170 0.0°C (0.0°F) Controller deadband for preheat temperature

loop Preht F/B Diff ADF 169 2.5°C (5.0°F) Preheat face and bypass OA differential Preht F/B Setpnt ADF 168 1.5°C (35.0°F) Preheat face and bypass OA setpoint Preht Int Tm ADF 169 60 Integration time for preheat temperature loop Preht LLim Diff ADF 169 5.5°C (10.0°F) Preheat low limit OA differential Preht LLim SP ADF 168 10.0°C (50.0°F) Preheat low limit OA setpoint Preht Lock Cmd BD 203 0 = Off Preheat lockout command Preht Lock Stat BD 20 0 = Off Preheat lockout status Preht OA Diff ADF 167 2.5°C (5.0°F) Preheat OA differential Preht OA Setpnt ADF 166 12.0°C (55.0°F) Preheat OA setpoint Preht Offset ADF 172 0.0°C (0.0°F) Controller bias for preheat temperature loop Preht PBand ADF 149 -11.0°C (-20°F) Proportional band for preheat temperature

loop Preht Setpoint ADF 168 10.0°C (50.0°F) Preheat setpoint Purge Command BD 194 0 = Off Purge command Purge Status BD 31 0 = Off Purge mode status Restart Delay ADF 224 1.0 Minute Power fail restart delay Restart Status BD 26 0 = Off Restart status Ret Vol DBand ADF 209 0 L/M (0 CFM) Controller deadband for return volume flow

loop Ret Vol Deriv Wt ADF 212 0 Derivative weight for return volume flow loop Ret Vol Int Tm ADF 208 20 Integral time for return volume flow loop Ret Vol Offset ADF 211 0 L/M (0 CFM) Controller bias for return volume flow loop Ret Vol PBand ADF 210 +700000 L/M

(+25000 CFM) Proportional band for return volume flow loop

Retrn Clg DBand ADF 136 11°C (20°F) Deadband for the return cooling temperature loop

Retrn Clg Int Tm ADF 132 600 Integration time for the return air cooling loop Continued on next page . . .


Parameter (Cont.)

Point Location


Retrn Clg PBand ADF 137 8°C (15°F) Proportional band for the return cooling temperature loop

Retrn Econ PBand ADF 133 11°C (20°F) Proportional band for the return economizer loop

Retrn High Limit ADF 144 26.5°C (80.0°F) Supply Air Reset - return air high setpoint Retrn Htg DBand ADF 134 0.5°C (1.0°F) Deadband for the return heating temperature

loop Retrn Htg Int Tm ADF 131 600 Integration time for the return air heating loop Retrn Htg PBand ADF 135 -11°C (-20°F) Proportional band for the return heating

temperature loop Retrn Reset Band ADF 145 -4.5°C (-8.0°F) Supply Air Reset - return reset band Return Air Enthalpy ADF 20 0.0 KCl/kg

(0.0 Btu/lb) Calculated return air enthalpy

Return Duct Area ADF 200 2.3 sq m (25 sq ft) Return duct area Return Fan Alarm BD 25 0 = Normal Return fan alarm Return Flow ADF 26 Calculated value Return volume Return Flow Mult ADF 201 1.00 Return airflow multiplier Return Setpoint ADF 129 24.0°C (75.0°F) Return air control - return setpoint Shutdn Off Time ADI 139 00:00 Hr:Mn Shutdown off time Shutdn On Time ADI 138 00:00 Hr:Mn Shutdown on time Shutdown Command BD 197 0 = Off Shutdown command Shutdown Status BD 28 0 = Off Shutdown mode status Static Deadband ADF 204 0.0 Pa (0.0 in. WG) Controller deadband for static pressure loop Static Deriv Wt ADF 207 0 Derivative weight for static pressure loop Static Int Tm ADF 203 20 Integration time for static pressure loop Static Offset ADF 206 0.0 Pa (0.0 in. WG) Controller bias for static pressure loop Static Prop Band ADF 205 -1000.0 Pa

(-4.0 in. WG) Proportional band for static pressure loop

Static Setpoint ADF 202 250.0 Pa (1.0 in. WG)

Static pressure setpoint

Summer/Winter BD 23 0 = Summer Summer/Winter mode status Summer/Winter BD 198 0 = Summer Summer/Winter mode status Supply Duct Area ADF 198 2.3 sq m (25 sq ft) Supply duct area Supply Fan Alarm BD 24 0 = Normal Supply fan alarm Supply Flow ADF 25 Calculated value Supply volume Supply Flow Mult ADF 199 1.00 Supply airflow multiplier Supply Ramp Step ADF 213 0.33%/sec Ramp step for supply fan in percent. Used at

startup. Supply VP Diff ADF 201 2.50 Pa

(0.01 in. WG) Velocity pressure setpoint for two speed supply fan

Supply VP Setpnt ADF 200 7.50 Pa (0.03 in. WG)

Velocity pressure differential for two speed supply fan

Temp Diff Setpnt ADF 150 4.5°C (8.0°F) Economizer switchover temperature differential

Continued on next page . . .


Parameter (Cont.)

Point Location


Unocc Dis Clg SP ADF 143 15.5°C (60.0°F) Unoccupied discharge cooling setpoint Unocc Dis Htg SP ADF 142 32.0°C (90.0°F) Unoccupied discharge heating setpoint Unocc Econ PBand ADF 235 0.0°C (0.0°F) Unoccupied proportional band for the

economizer loop Unocc Flow Diff ADF 214 0 L/M (0 CFM) Unoccupied flow differential Unocc Setback ADF 148 4.5°C (8.0°F) Unoccupied setback Unocc Setup ADF 147 4.5°C (8.0°F) Unoccupied setup Vent Command BD 193 0 = Off Vent command Vent Status BD 30 0 = Off Vent mode status W/C Zone Diff ADF 130 2.2°C (4.0°F) Warmup/cooldown zone differential W/C Zone Setpnt ADF 144 22.0°C (72.0°F) Warmup/cooldown zone setpoint Warmup/Cooldown Command

BD 195 0 = Off Warmup command

Warmup/Cooldown Status

BD 29 0 Off (0 On) Warmup/cooldown status

X Preht PBand ADF 171 -33°C (-60°F) Proportional band for preheat temperature loop

Zone Clg DBand ADF 136 11°C (20°F) Deadband for the zone cooling temperature loop

Zone Clg Int Tm ADF 132 600 Integration time for the zone cooling loop Zone Clg PBand ADF 137 8°C (15°F) Proportional band for the zone cooling

temperature loop Zone Econ PBand ADF 133 11°C (20°F) Proportional band for the zone economizer

loop Zone Htg DBand ADF 134 0.5°C (1.0°F) Deadband for the zone heating temperature

loop Zone Htg Int Tm ADF 131 600 Integration time for the zone heating loop Zone Htg PBand ADF 135 -11°C (-20°F) Proportional band for the zone heating

temperature loop Zone Integration ADF 144 0 Integration time for zone temperature loop Zone Prop Band ADF 145 4.5°C (8.0°F) Supply Air Reset - proportional band for zone

reset loop Zone Setpoint ADF 129 22.0°C (72.0°F) Zone Control - zone setpoint

Controls Group 507 E. Michigan Street www.johnsoncontrols.comP.O. Box 423 Release 8.0Milwaukee, WI 53201 Printed in U.S.A.

Date post:	16-Oct-2021
Category:	Documents
Upload:	others
View:	0 times
Download:	0 times

AHU Applications Application Note - Johnson Controls

Documents