Tempered Water A/C Systems ❖❖❖❖❖ INSTALLATION GUIDE

For LP-14Revised: 8-16-05L-0682 ❖❖❖❖❖ English

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WARNING

This manual contains essential safety information concerningthe operation and maintenance of your Cruisair system. It isvery important that you read and understand the contents ofthis manual thoroughly before using the equipment, and youshould keep it on your boat for future reference. If there are anystatements in this manual that you do not understand, contactthe Dometic Corporation Service Department or your localdealer for assistance.

IMPORTANT

NOTICE

Your Cruisair air conditioning system uses a refrigerant gasknown as R-22. Federal law forbids the intentional release ofthe refrigerant gas to the environment. You should makecertain that any field service is performed by a competentspecialist with the proper equipment to prevent any loss of R-22 during servicing.

Cruisair tempered water components are well engineered andbuilt, and thoroughly tested at the factory. However, a circu-lated water system will only perform as well as the quality ofthe installation. This consists mainly of plumbing and wiring,which can be handled by most boatyards; but each aspect ofthe installation should be thoroughly planned to minimize timeconsuming mistakes and maximize performance.

One of the most common source of problems with thesesystems is the water plumbing. Always be sure to doublecheck connections for correct placement and tightness. Asimple rule about water connections would be that the returnlines are above the supply. This is so that any air in the systemwill travel upwards with the water flow.

When selecting the site for a piece of equipment, try to choosea location which will keep noise to a minimum, but also allowfor future servicing. The Dometic Corporation Applicationsdepartment is available to help with the design of the system,or to answer any specific questions one may have about eitherthe equipment or the installation.

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Table Of Contents

INSTALLATION GUIDE

TEMPERING UNITS .................................................................................................................................................................... 4Location ........................................................................................................................................................................... 4Lifting the Unit ................................................................................................................................................................. 4Mounting ......................................................................................................................................................................... 4Water Connections ......................................................................................................................................................... 5Wiring .............................................................................................................................................................................. 5

CONTROL PANELS ..................................................................................................................................................................... 6Location ........................................................................................................................................................................... 6Wiring .............................................................................................................................................................................. 6Owner’s Control .............................................................................................................................................................. 7Pump Relays ................................................................................................................................................................... 7Circuit Breakers .............................................................................................................................................................. 7Variable Frequency Drives ............................................................................................................................................. 7

SEAWATER SYSTEM .................................................................................................................................................................. 8Through Hull Fitting ........................................................................................................................................................ 8Strainer ............................................................................................................................................................................ 8Pump ............................................................................................................................................................................... 8Wiring .............................................................................................................................................................................. 8Pipe Sizing .................................................................................................................................................................... 10Spare Pumps ................................................................................................................................................................ 10

CIRCULATING WATER SYSTEM ............................................................................................................................................. 11Guidelines ..................................................................................................................................................................... 11Insulation ....................................................................................................................................................................... 11Leak Testing .................................................................................................................................................................. 12Pipe Sizing .................................................................................................................................................................... 12Pumps ........................................................................................................................................................................... 12Expansion Tank ............................................................................................................................................................ 13Balancing Flow Control ................................................................................................................................................. 13Two-Pump Systems ...................................................................................................................................................... 14

AIR HANDLER UNITS ................................................................................................................................................................ 15Location ......................................................................................................................................................................... 15Mounting ....................................................................................................................................................................... 15Water Connections ....................................................................................................................................................... 16Aux. Heat ....................................................................................................................................................................... 16

AIR DISTRIBUTION ................................................................................................................................................................... 17Return Air Grill .............................................................................................................................................................. 17Discharge Grill .............................................................................................................................................................. 17Ducts ............................................................................................................................................................................. 17

CABIN CONTROLS .................................................................................................................................................................... 19Rotary Switches ............................................................................................................................................................ 19SMX Systems ................................................................................................................................................................ 19

FINAL INSPECTION .................................................................................................................................................................. 21

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INSTALLATION GUIDE: Modular Tempering Unit Installation

LocationThe tempering unit is usually located in the engineroom, or other mechanical space. When choosing alocation keep in mind this is an electromechanicalpiece of equipment and on occasion may needmaintenance, repair or replacement. Always provideadequate visual and physical access.

LiftingWhen lifting framed units, do not lift by the upper partof the frame. Only lift by the base. Some units haveeye-bolts which can be used for lifting.

MountingIndividual modular units are contained in a conden-sate pan, which is then secured to the boat. Mountthe unit securely on a horizontal surface of sufficientstrength to withstand both static load and dynamicforces when boat is in motion. Secure the unit on allfour corners using pre-installed mounting brackets(shown in figure 1). Do not bolt through bottom ofpan.

Figure 1. Modular Tempering Unit

The pan of the unit has two 3/8 FPT condensatedrains, one at each end. Connect these outlets toproper tubing and route to an appropriate locationsuch as an overboard fitting or sump. Do not permitcondensate to puddle in the bilge.

Mounting FramesHoles are provided in the base rails to secure theframes. If stacking one frame on top of another, theframes will overlap and the units should be boltedtogether. Be sure to secure the top of the frame toprevent movement.

Water ConnectionsFigure 1 shows water connection locations. Unionsand service valves should be used on the waterconnections for ease of servicing in the future.Always use full flow ball valves.

The loop water connections are the bronze fittings,with the inlet being the lower, and the outlet is theupper.

The sea water pipes connect to the plastic headers inthe same fashion, lower inlet and upper outlet. Notethat the seawater fittings can be changed so theconnections are on the top and bottom of the unit,instead of on the end, as from the factory.

Support all the piping by the boat’s structure and donot rely on the equipment for support. Figure 2 showsthe water connection sizes.

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Water HeadersSee figure 3 for water manifold connection sizes.Also, it is a good practice to use reverse returns onseawater plumbing to ensure equal water distributionto all tempering units.

WiringThe wiring for the modular tempering unit is verysimple. The control wires have polarized plugs whichmate with plugs on the wire leads from the controlpanel.

On single phase units, the compressor power leadfrom the control panel connects to the terminal strip inthe electrical box mounted on the tempering unit.

The power wiring for three phase models will simplyhave leads from the control panel that connectdirectly to the compressor. Figure 3 shows a typical,two-unit system, wiring schematic.

Note that the air handling units are not electricallyconnected to the tempering unit or panel control.

Figure 3. Typical Wiring Schematic For Tempered Water Systems.

Figure 2. Tempering Unit Water Connections

Tempering Units Seawater Loop WaterFittings* Fittings*

3 or 4 ton 1" 1"

5 or 6 ton 1" 1 1/4"

Multiple Units Headers Headers

2 Units 1 1/2" 1 1/2"

3 Units 1 1/2" 1 1/2"

(Up to 144,000BTU/hr)

3 Units 2" 2"

(Over 144,000BTU/hr)

4 Units 2" 2"

* All fittings are FPT.

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INSTALLATION GUIDE: Modular Control Panels

LocationThe control panel contains all of the necessarycontrols to operate the tempering unit. Mount thepanel to a flat vertical surface.(See figure 4). Thelocation chosen should be free from water spray andheavy moisture and should also provide adequateaccess both visual and physical. The location shouldalso be close enough so the factory connected leadswill reach the tempering unit. The panel comesstandard with 10' of wire to connect to the temperingunit. Longer leads can be provided on specialrequest.

Single Panel WiringThe wiring of the control panel will consist of con-necting the pre-wired leads to the tempering unit,connecting field installed power wiring to the powerinput terminal strip, and connecting field installedcontrol signal to the seawater and circulating pumprelays. All field wiring should only be done byqualified people and the correct wire size and properterminals should always be used. See figure 4 forgeneral wiring schematic.

Multi-Unit Panel WiringMulti-unit control panels are similar to the singlepanels in that all control leads are provided with thepanel, and plug directly to the tempering units. Thecompressor leads are also the same as on thesingle units, whether single or three phase systems.If pump relays are incorporated into the controlpanel, then the pump leads will be field wired fromthe proper terminal strip in the control panel to theappropriate pump.

Temperature SensorsThe multi-unit panel will have temperature sensorsfor sensing return and supply loop water tempera-ture. The return loop water temperature sensor is forsensing stage temperature setpoint. The supply loopwater temperature sensor is for sensing freeze andhigh limit temperature conditions. Each sensor islabeled. These should be placed as close to thetempering units, on the main water headers, aspossible so that true temperature is measured.Also, if CPVC piping is used, a sensor mount (suchas MDC # A-416 or A-417) should be used, sincethe plastic pipes will not transfer heat well enoughfor accurate sensing. Insulate the piping and sensormount together.

Figure 4. Modular Unit Panel.

Multi-Modular PanelsMulti-unit control panels will follow the same guide-lines as the single panel. If multiple tempering unitsare provided in a frame, the panel can be mountedon the frame itself.

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Owner's ControlThe MSC-1KCB owner’s control for single controlpanels is mounted in a convientient location, andconductor wire is run to terminal strip on controlpanel. The owner’s control can only operate onepanel.

For the owner’s control used with a combo-panel(MSAH-1MHAB), the momentary switch is mountedwhere desired, with 5 conductor control wiring run tothe terminal strip on the combo-panel. Multipleowner’s controls can be installed, if desired.

There is also a model available with digital tempera-ture display of the Supply and Return Loop water.

Pump RelaysThere are numerous types of relays that may beused, but there are a few general guidelines thatshould always be followed. The location should befree of water spray and heavy moisture, and ad-equate accessibility should be provided to allow forinspection of fuses or breakers. 24 VAC triggersshould always be used.

The relay will only need to receive control wire fromthe modular control panel and the power wiring willbe field installed from the boat’s power distributionand then on to the pump. All field wiring should onlybe done by qualified people and the correct wiresize and proper terminals should always be used.

Circuit BreakersBreakers are sized for short circuit protection ofcurrent carrying conductors. Curve 10 breakersshould be used for the tempering units due to thestarting loads of the compressors. Always checkwith regulation codes (ABYC, section E8) for finalsizing of breakers or wiring.

Variable Frequency DrivesThese units should be mounted close to the com-pressors, in an accessible place. The wiring fromthe control panel will feed to the VFD, and then onto the tempering unit. The tempering unit must havea 3 phase compressor, but the VFD can use either 1or 3 phase input power. The control panel shouldmatch the ship’s power, whether 1 or 3 phase. Seethe instruction sheet for specific wiring details, orcontact the Dometic Corporation - Cruisair, Applica-tions Department.

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INSTALLATION GUIDE: Seawater System

Through Hull FittingA separate through-hull fitting and seacock should beused for each air conditioning seawater pump.

Special attention should be given to the location ofthe inlet through-hull fitting. A dedicated through-hullfor the air conditioning system should be located nomore than six inches from the keel, and ahead of thestuffing box and engine intake through-hull. Do notattempt to draw seawater from the engine or genera-tor through-hull fitting. If a sea chest arrangement isused, special precautions must be taken to ensurethat the tempering unit will have adequate raw waterflow.

A scoop-type through-hull is preferred for mostinstallations, especially on faster boats. It should befacing forward and located near the keel orcenterline, where it will always be underwaterwhenever the air conditioner is running. Beware ofthe change of location of the through-hull fittingrelative to the waterline, given the motion of the boat.Special attention should be given to sail boat applica-tions, as the extreme heel angles they experiencecould result in the through-hull fitting coming out ofthe water and air locking the pump.

StrainerThe in-line basket type strainer should be placed inthe seawater line between the seacock and thepump. It should be situated to provide easy accessfor regular cleaning. Make certain the seawaterstrainer is oriented properly. The arrow on thestrainer housing should point in the direction of thewater flow, toward the seawater pump.

Centrifugal PumpsThe seawater pump must be placed in a location thatis below the water line whenever the air conditioningsystem is running, and typically near the temperingunit. The centrifugal pump is not self-priming andwater must flow freely to it. The pump may becomeair locked if air is drawn into the seawater system.Once again, sailboats may require special consider-ations to prevent air locking when heeling.

Bolt the pump securely on a horizontal surface withthe discharge connection as the highest point. Thepump should be installed with resilient mounts toprevent vibrations from being transmitted to thestructure of the boat. Make certain that the pump iseasily accessible for service.

The orientation of the pump head should always havethe discharge pointing upward with a straight run ofvertical pipe leaving the pump. This will help preventair from becoming trapped in the pump head.Trapped air is a common nuisance that preventsproper flow and may even damage the pump. Besure the location chosen will not allow the pump to bestepped on or hit by other moving machinery.

The fittings connecting the pipe to the pump shouldprovide valves and unions to allow removal the pumpfor maintenance and repair. Note that the piping isdetermined by the volume of the water flow, not theconnection sizes on the pump head.

The immediate pipe to the inlet of the pump headshould be straight for a length of at least 12" so auniform flow of water enters the pump.

Do not install any type of check valve in the seawatersystem as this can cause the pump to air lock if anyair gets into the system.

Pump WiringThe only wire to be connected to the pump will be thepower wires from the output of the pump relay. Payclose attention to the wiring schematic label on theside of the pump motor. Many of the pumps used inCruisair systems are dual voltage. Determine thesupply voltage, and connect the pump accordingly.Connecting the wiring incorrectly could destroy themotor. There are some cases where the pump issupplied with a dual rotation motor. Be sure that thepump is rotating in the proper direction, usuallyindicated by an arrow on the pump head. All fieldwiring should only be done by qualified people andthe correct wire size and proper terminals shouldalways be used.

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INSTALLATION GUIDE: Importance of a Self-Draining Seawater System

Whenever a centrifugal-type seawater pump is used,it is imperative that the seawater plumbing be routedcontinually uphill, without loops and dips, from thepump to a high point between the condenser assem-bly and the overboard discharge. The system is saidto be self-draining because if the boat were to belifted out of the water, all of the water would drain outof the system. This will help prevent air lock if air isever drawn into the system, and also makes winteriz-ing the system much easier.

A properly plumbed system is absolutely necessary.Air can easily get into the system if the boat is inheavy seas or makes a sharp turn. If this air is not

expelled, it can become trapped in the pump. With airin the pump, no pressure can be produced and thewater flow stops.

Figure 5 shows a properly plumbed system. In thisdrawing, the high point of the system is at the over-board discharge. This will allow any air which may bedrawn into the system to escape.

If the discharge must be lower than the temperingunits, there should only be one high point. This way,when the seawater pump cuts off, the water in thesystem will drain out (to the water line), preventingthe system from becoming air locked.

Figure 5. Typical Tempered Water Piping Layout.

TemperingUnit(s)

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Seawater Pipe Sizing ChartTempering Unit Pipe orCapacity Range Hose Size(BTU/hr X 1000) (ID)

24 - 30 3/4"

30 - 72 1"

72 - 144 1 1/4"

144 - 180 1 1/2"

180 - 360 2"

360 - 720 2 1/2"

Seawater PipingThe seawater cooling system consists of a through-hull fitting, water shut-off valve or seacock, strainer,seawater pump, water pipe (schedule 80 CPVC orcupro-nickle) or marine grade hose, and overboarddischarge fitting. Piping should be secured firmly withthe correct fittings.

Route the plumbing in a constant uphill to preventwater trapping. Avoid loops, dips and kinks in theseawater pipe. Secure the piping well, as neither thepump nor the tempering unit is designed to supportthe weight of the piping and water.

If you are using a single seawater pump to supplymultiple tempering units, that are not already framedand plumbed together, special attention must begiven to ensure even water distribution to each unit.Be careful to avoid loops and dips at this location.Reverse returns should be used whenever possible toensure equal seawater flow to all units.

Always double clamp hose connections.

Pipe SizingSee figure 6 for recommended pipe sizing. If thehose or pipe size is a long run or with many fittings,use the next larger size.

Overboard DischargeA separate overboard discharge should be used foreach tempering unit, but a manifold and a commonoverboard will work if properly sized. Overboarddischarge fittings should be located one or two inchesabove the vessel’s level water line. This will allowvisual checking of the water flow, and will be closeenough to the water’s surface to prevent excessivesplashing noise. If the discharge is fitted below theheeled water line, a seacock should be fitted perABYC standards 4-27 4a.

Spare PumpsWhen a back-up pump is to be installed along withthe main pump, there are some special consider-ations which should be followed to ensure properoperation.

The backup pump should be installed in parallel withthe main pump, with full flow valves on the inlet andoutlet of both pumps to allow total isolation of eitherpump. A power transfer switch must be provided toselect which pump operates. This should be locatednear pumps to lessen the chance of running a drypump, which could damage the pump and/or com-pressor.

To ensure that the spare pump will operate whenneeded, the main and back-up pumps should beswitched at regular intervals so they are run evenly.Another option would be to completely “winterize” theback-up pump (i.e. keep it dry). This should helpkeep the pump seals in good condition and preventthe pump impeller from freezing up.

Labels identifying the switch and valves in the systemwould help prevent operator error, and a note on thepumps to tell the user to keep both of the valves onthe inactive pump closed might stop a well meaningperson from opening all valves which would justcirculate water in the pump loop.

An easier and less expensive method might be toinstall the main pump with cut off valves and unionson the intake and discharge. This would allow afailed pump to be easily replaced with a spare carriedaboard. The spare pump could have union fittingsattached for quicker a installation, if desired.

Figure 6. Seawater Pipe Sizes.

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INSTALLATION GUIDE: Circulated Water Loop Installation

GuidelinesA typical system will have the circulating pump as thelowest point in the water loop (or as low as possible),with the tempering unit being the next highest pieceof equipment followed by the air handlers. Ideally,the only changes in the vertical direction will occur atthe air handlers where the built in vents can bleedany trapped air.

PipeMDC only recommends “L” type copper or schedule80 CPVC. The use of any other pipe is the installer’sdecision. Always follow manufacturer’s directionswhen installing piping.

Main VentA main vent should be installed at the highest point inthe system, with it’s discharge routed back to theengine room so as to allow the system to be filledand vented at the same time. (1/2" piping is suffi-cient)

System DrainThe system drain is placed at the lowest point in theloop to allow for easy servicing.

Air TrapsA vent should be installed wherever an air trap ispossible. All of our air handling units and temperingunits have manual vents to bleed air from the system.All piping should be installed so that the air handlersare local high points, with constant inclining anddeclining slopes. Any time the piping reverses thevertical direction, an air or water trap is created. Airtraps can cause noise, and even stop the flow ofwater; and therefore must have a means of ventingthe air. They are a real nuisance when trying to filland bleed a system. A water trap will preventcomplete draining of the system (for repair or winter-izing), so there must be a drain at the trap.

SupportAll piping must be secured to support its own weight(including the water in the system.) Neither thetempering unit nor the air handlers are designed tosupport the weight of the piping.

InsulationAll piping should be thoroughly insulated to preventsecondary condensation. Improper insulation is acommon problem with tempered water systems, andvery difficult to find and correct, even after the waterdamage is noticed. A gap in the insulation willproduce condensation on the pipes, which can rundown inside the insulation to a different location.

We recommend 3/4" thick insulation on the pipes.Supply and return piping should always be insulatedindividually.

When putting the recommended closed cell foaminsulation over the pipes, cover the ends of the pipingto prevent foreign material and moisture from gettinginside the piping. After checking for leaks, insulatethe connections and tee-joints to prevent secondarycondensation. Any exposed pipe can sweat andcause water damage so it is very important to insu-late the piping thoroughly.

If using split insulation, seams should be closedtightly, sealed with glue or tape. All water fittings,connections, valves, etc. in the system should be wellinsulated, after the system is leak tested.

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Leak TestingIt is a good practice to leak test the loop plumbingthroughout the installation of the system, as well asafter the installation is complete. This is especiallyimportant when joints will be concealed and thereforevery difficult to get to in case of a leak.

A simple procedure of pressurizing the pipes with airwill indicate whether that section of plumbing issound. The piping should be able to hold 75 psi overa 12 hour period (minimum). Note that fluctuations inpressure may be noticed due to temperaturechanges, but a drop of over 5 psi indicates a leak,which should be found and fixed.

Large leaks will be easily heard, but small leaks canbe difficult to find. There are several ways of locatingsmall leaks:

• Add some water to the system before pressurizingwith air. The water will travel to the leak and add tothe noise as it escapes, as well as creating a wetspot.

• If a joint is suspected to be leaking, a liquid leakdetector (such as soap bubbles) can be applied topinpoint the problem.

• Electronic devices are available which can helpidentify leaks by “listening” for high frequency noisescharacteristic of a leak.

Finding leaks before the initial filling of the loop withwater will save you from having to drain an entiresystem to fix leaks, as well as avoiding expensivewater damage to a completed vessel.

Pipe SizingSee figures 7 and 8 to select the proper pipe sizes.These recommended sizes are designed to keeppressure losses to a minimum.The next larger pipe should be used whenever thecapacity being served is near the upper limit of therange and any of the following is true:• The pipe run has numerous bends.• The run is an extremely long distance.• There is a large vertical rise.• Possibility of adding more capacity.

Note that over sizing pipes can be harmful too. Thedrastic changes in water velocity can cause extralosses and noise in the system. It can also make it

Circulated Water Pipe Sizing ChartCapacity Range Pipe Size(BTU/hr X 1000) (ID)

3 - 12 1/2"

12 - 24 3/4"

24 - 48 1"

48 - 96 1 1/4"

96 - 180 1 1/2"

180 - 360 2"

360 - 660 2 1/2"

Figure 7. Loop Pipe Sizing

difficult to remove air.

Circulation PumpThe circulating pump should be located near thetempering unit, pumping water into the tempering unitfirst, and then through the loop. This will help ensurethat the tempering unit is not starved for water.

The pump discharge should be directed in a verticallyupward position, with a straight run of vertical pipeleaving the pump, to prevent air from becomingtrapped in the pump head. Trapped air is a commonproblem which can prevent proper flow causing flowswitch shut downs, and can eventually damage thepump.

The immediate pipe to the inlet of the pump headshould be straight for a length of at least 12" so auniform flow of water enters the pump.

The pump should be protected from being steppedon or hit by other objects and all connecting pipingshould be well supported so as not to put any unduestress on the pump head. Resilient pump mountsshould be used to prevent excess vibration frombeing transmitted to the boat structure.

The fittings connecting the pipe to the pump shouldprovide valves and unions to allow removal the pumpfor maintenance and repair. Always use full flow ballvalves.

Note that the size of the system piping is determinedby the volume of the water flow, not the connectionsizes on the pump head.

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Expansion TankThe expansion tank, pressure gauge, and fill valveshould all be connected on the return side of the loop,at the inlet of the circulating pump. The tank shouldbe fastened securely so as not to put any stress onthe connecting pipe and can be mounted in anyposition. The gauge should be located to allow goodvisibility when operating the fill valve.

It is a good idea to install a service valve at theexpansion tank to ease future maintenance. How-ever, the valve handle should be removed to preventthe tank from being isolated from the main loop.

When the fill valve is connected permanently to thepotable water supply, a proper back flow preventermust be installed, per ABYC.

If an electric or a fuel fired water heater is used toheat the loop, a 30 psi relief valve must be installedand the discharge plumbed to a safe location.

Balancing Flow ControlThe balancing flow control is a flow regulator that isused in a system where the total air handler capacityis different from the tempering units. BecauseCRUISAIR tempered water components use flowcontrols to regulate the flow through each unit, a“balanced” system can be achieved which eliminatesthe need to manually adjust the flow with valves.

Typically, the air handlers have a larger capacity thanthe tempering units. In this case, the BFC is installed

in parallel with the tempering unit and balances theloop by allowing only a certain amount of water tobypass the unit.

In the case of the tempering units having morecapacity than the air handlers; the BFC is installed inparallel with the air handlers so enough water flowsthrough the tempering unit. See figure 9.Balancing flow controls are available in many differ-ent capacities. Connections range from 1/2" FPT to1 1/4" FPT.

Figure 8. Circulated Water Piping.

Figure 9. Balancing Flow Control Installations.

Tempering Unit CapacityLess Than Air Handlers

Tempering Unit CapacityGreater Than Air Handlers

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Two Pump SystemsWhen larger systems are installed, (tempering unitcapacity over 20 tons) often two circulating pumpsare used to ensure proper water flow. One pump(sized to loop capacity) will serve the air handlers ,and a second pump (sized to tempering unit needs)will draw water from the air handler loop and supplythe tempering units.

The balancing pipe allows both pumps to provide thecorrect water flow to each side of the loop. This is aself balancing system, and a BFC is not needed. Seefigure 10.

A full flow valve can be installed in this balancing pipewhich will allow one pump to supply the entire sys-tem, providing at least partial operation in the case ofa pump failure.

The minimum size of the balancing pipe can befigured from figure 10 by using the difference incapacities to select pipe size.

Figure 10.. Typical Two-Pump Installation

Two Pump System

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INSTALLATION GUIDE: Air Handler Installation

LocationIn general, tempered water air handlers follow thesame installation guidelines as direct expansioncooling units.

Because of the diversity of available air handlermodels, you have a great deal of flexibility in select-ing the location. All CRUISAIR air handlers usesquirrel-cage blowers which are more efficient airmovers than fan units.

Blow-through models are used when the air handleris to be mounted directly behind the discharge grillwithout ducts. These can also be used beneath aflybridge or other overhead space, for direct dis-charge downward into the compartment below.

Draw-through units provide better circulation, andmore flexibility, as the discharge can be ducted toone or more discharge grills, located a further dis-tance from the return air grill. On draw-through units,the blower can be rotated to provide the easiest airpath for discharge.

Figure 11 shows typical ducted air handler installa-tion.

Ideally, the air handler discharge grill should be ashigh as possible in the compartment, with three feetabove the floor being a minimum.

On draw-through models, it is not necessary that thecoil be placed directly behind the return air grill; butan unobstructed path, with at least 2" of air spacearound the units, must be provided for the air to getto the coil. The area housing the air handler must besealed from engine room and bilge area.

The unit must be accessible for service and mainten-ance, and oriented so the water connections caneasily be reached. The air filter should be checkedand cleaned regularly.

It is always good to mount power logic boxes (forSMX controls) in an easily accessible place, for futureservicing. In the case of units with integrated powerlogic boxes (such as CBBX models), the box can beremoved from the air handler and remote mounted foreasier access.

You should measure carefully for horizontal andvertical clearance prior to proceeding with installation.It is a good practice to place each component physi-cally in the area you have selected to be sure thatthere is enough space and that connections can beeasily made.

MountingLocate the air handler on a suitable horizontalsurface. CRUISAIR air handlers are provided withrubber isolation mounts. Secure all four mounts tothe surface.

Mount the air handler so that the condensate pan willdrain properly. All air handling models have integ-rated mounting frames or the condensate pan itself isthe base of the unit.

Route the condensate drain hose steadily downhill sothat the condensate flows freely to an overboardfitting or sump. Do not permit condensate to puddlein the bilge. Most CRUISAIR air handlers have twocondensate drains, one at each end. It is recom-mended that you use both drains for best results. Inthe case of sail boats, where heel angles could causespillage or a back flow, it is best to route the drains toopposite sides of the boat.

Figure 11. Typical CBB Type Installation.

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Water ConnectionsAll Cruisair air handlers have female pipe threadconnections. Units of 12,000 BTU/hr and smaller use1/2" FPT; and units 15,000 - 24,000 BTU/hr use 3/4"FPT. The piping must slope upward to the air handlerto encourage air to travel to the vent. The lowerconnection is the inlet or supply, and the upperconnection is the outlet or return.

One improperly connected air handler can affectthe performance of the entire system.

The fittings used to connect the air handlers mustinclude valves and unions for service and removal ofthe air handler. Use full flow ball valves.

Auxiliary Electric HeatingRefer to figure 12 for correct mounting positions ofelectric, in-line, duct heaters. The safety devices maynot work correctly if mounting position is incorrect..

Air Handler WiringThe air handlers will receive power from a sourceseparate from the tempering units. Multiple airhandlers can often be on one breaker, but wheninstalling units with integrated electric heat, separatebreakers should be used.

Figure 12. Correct Mounting of In-line Duct Heaters.

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INSTALLATION GUIDE: Air Distribution System

Return Air GrillsRefer to air handler specification sheets for guidanceon selecting the proper grill size. Too small of a grillwill restrict the blower, limiting the capacity of the airhandler.

The return air grill should be located so there isunobstructed airflow to the units coils. Return airducts between the return air grill and the air condi-tioning unit is not normally necessary, and should beavoided. The evaporator coil need not be locateddirectly in front of the return air grill, as long as airflowfrom the grill to the coil is unobstructed (2" of airspace is sufficient). This allows installation of the unitsuch that discharge air can be directed in the mostefficient manner. Be sure that the enclosure issealed so that air is not drawn from unwanted areas.

Most air handling units are supplied with a lint screenor filter to prevent the coil from collecting dirt or lint.A filter can be located at the return grill, should thefilter on the coil be inaccessible for cleaning. How-ever, the filter on the coil should be removed whenusing a filter on the return grill, so that only one filteris used.

Discharge GrillsRefer to air handler specification sheets for guidancein selecting the proper size grill. It is important toselect the proper size and design of grill to ensuregood airflow, with minimum noise. Also, wood grillsare less likely to “sweat” than metal grills.

Some air handler models are supplied with hoseadapter fittings; others require an adapter be pur-chased separately. Always use the proper size grillsand ducting. If in doubt, slightly bigger is better. Whentwo or more air handlers are run in parallel off one fanspeed control, the ducting should be kept as equal aspossible for better fan speed control.

When used with flexible ducts, a plenum chambershould be incorporated behind the discharge grill.Location of this grill should be as high as possible inthe cabin, and oriented so that air flow betweendischarge and return encompasses as large an areaas possible in the cabin. Care should be taken toavoid short cycling, a situation where the conditionedair is returned to the coil without being mixed thor-oughly with the cabin air.

DuctingInsulated flexible ducts, or built-in duct work may beused to route air from the draw-through air handlersto the discharge grill.

When flexible ducts are used, there should be as fewbends and turns as possible. Pull all of the ductingtightly to prevent kinking and collapsing of the duct.Attach duct to grill plenum and hose adapter securelywith no air leaks. Plenums are used with flexibleducts to direct air in the proper direction. Figure 13shows several typical plenum configurations.

When built-in or rigid ducts are used, they should beinsulated and there should be a flexible transition(marriage band) between the duct and blower.

Blow-through type air handlers can be installeddirectly behind the discharge grill, and ducts areunnecessary. For an overhead installation, air can bedischarged directly into the compartment usingmarriage bands.

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Figure 13. Typical Plenum Configurations

Figure 14. Duct and Grill Sizes

3,000 5" 40/260 70/4504,500 5" 40/260 70/4506,000 5" 40/260 70/4507,500 6" 60/390 100/6509,000 6" 60/390 100/650

12,000 7" 80/520 140/90015,000 8" 100/650 200/130018,000 8" 100/650 200/130024,000 9" 140/900 260/1680

CBLB Type

Air Handler Duct AndMinimum Grill Sizes

Air Handler Duct Discharge ReturnCapacity SIze (in2/cm2) (in2/cm2)

CBB Type

18,000 2x 6" 2x 60/390 200/130024,000 2x 7" 2x 80/520 260/1680

CBH Type

6,000 - 70/450 70/45012,000 - 140/900 140/90018,000 - 200/1300 200/130024,000 - 260/1680 260/1680

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INSTALLATION GUIDE: Installing Cabin Controls

Rotary Switch LocationThe control unit should be mounted on a convenientbulkhead where it can be easily reached by theoperator. There should be rear access, with suffi-cient clearance behind the unit for the electricalwiring connections, the protective cover, and ventila-tion.

The unit should be close enough to the air handler sothe temperature sensing bulb can be placed in thepath of the return air. In most cases the bulb isattached behind the return air grill or directly to theair handler. Be sure the bulb is not touching anymetallic surfaces.

For switch assemblies with two sensing bulbs, thelarge one goes in the return air path, and the smallerone in the discharge air.

SMX Series Keypad LocationSelect a location on a vertical surface; this can be aninside or outside wall, partition, or other permanentstructure, with rear access for wiring. The controloperates on low voltage and is certified ignition-protected, so the wiring poses no hazard. The spacebehind the keypad does not have to be ventilatedsince the control does not produce heat.

SMX Keypad InstallationTo be operated satisfactorily, the keypad controlshould be installed so it is both visible and acces-sible. Overhead locations are discouraged sincethey make operation difficult. In staterooms, thecontrol should be installed so it is visible, and ifpossible, accessible from the bed.

Cut the hole for the keypad control. Check that the fitis correct, and make sure the printed circuit board isclear of the bulkhead and no objects of any kind arein a position to contact the SMX circuitry.

Plug in the interconnect (CX) cable, which is routedto the power/logic box. Refit the keypad and securewith four No. 6 x 3/8 screws. Hook the plastic coverat the top, press it flat from the top down, and snap itin place at the bottom.

Warning: Make sure all LED’s are lined up correctlywith the holes in the plate before snapping on theplastic cover. If an LED is not properly positioned, itwill break.

SMX Power/Logic Box InstallationThe SMX power/logic board is ignition-protected,enclosed, and can operate in ambient temperaturesup to 130° F. The P/L box is NOT waterproof andmust be placed where it will NOT get wet. Also, thecomponents produce heat during operation, and mustbe installed in a ventilated location.

The box may be installed in any position, although ahorizontal surface is best for shock resistance if theequipment is operated in rough seas. In selecting alocation for the power/logic box, keep in mind thataccess should be easy for trouble shooting.*

* On air handlers with an integrated power/logic box(CBBX type), the power/logic board will be pre-wired,with a wire loom connecting to the electrical box onthe air handler. If an air handler is in a location whichis difficult to access, it is often a good idea to removethe box from the air handler and remote mount it, tosimplify future servicing.

After selecting a suitable location, where it is acces-sible for wiring as well as for service, secure the boxwith the appropriate screws and flat washers.

TSE InstallationThe temperature sensing element (TSE) is a ther-mistor which is used to measure air temperature. Theactual sensor is 1" long by 1/4" diameter and isconnected to a shielded cable of different lengths.

For best results, the sensor should be placed in thereturn air path, usually behind the return air grill. Italso may be placed in front of the air handler coil (ason air handlers with integrated P/L box). Under nocircumstances should the sensor touch the coil, or anymetallic objects as the air temperature reading will notbe correct. Also, do not place the sensor in thedischarge air.

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The SMX system can be programmed for intermit-tent fan operation if desired (the fan cycles off whenthe temperature is satisfied). However, the ther-mistor moved from the return air path, and wallmounted on an inside surface, not subject to anyheat from outside the area (including direct sun-light). Operating in this mode will result in largertemperature swings than when the fan is constantlycirculating air.

The TSE cable simply plugs into the 3-prong connec-tor on the power/logic board. Pay particular attentionto pin alignment when plugging in cord.

Outside TSE (Online only)When installing the optional TSE outside thermistor, astandard TSE, available in many different lengths, isused. Only one is needed for the entire system,since the data is communicated around the loop.

The TSE is waterproof, and should be installed in theoutside air, but under an overhang or coaming whereit is shaded from the sun. Also, it should not betouching any metallic surfaces. The TSE plugs intothe “OUTSIDE” plug connection on the Online P/Lbox.

CX CableThe interconnect cable is a shielded cable, with 4 pinplugs on both ends. This cable is available in lengthsfrom 10 to 60 feet.Route the cable, which carries low voltage DC, fromthe keypad to the P/L box. Plug in at both ends.

Net CablesThe NET cables (CN) are connected to each P/L boxin the system The cable plugs to the output of one P/L box to the input of the next box. Each P/L boxshould be connected in line with the others.

Convenience PanelThe convenience panel connects to a Online keypadwith a ribbon cable. The ribbon cable is available in 2and 4 foot lengths. A system can have as manyconvenience panels as keypads.

Power ConnectionsThe SMX can be used with 115 or 230 volt systems,but the correct P/L box should be used. The internalvoltage plug or slide switch should be set for thesystem voltage. If the voltage of a board must bechanged, and aux. heat is to be used, the loadresistor used on the aux. heat relay circuit must alsobe changed to the correct size. Contact the MDCapplications department.

Air Handler ConnectionsThe ORANGE and WHITE/RED wires as well as aground wire should be connected to the blower motoron the air handler. If a two speed blower is used, theORANGE wire is high speed, the YELLOW wire islow speed, and the WHITE/RED is N or L2.

Bypass ValveThe BLUE and WHITE/RED wires, and a ground,should be connected to the correct terminals on thebypass valve.

Change Over ThermostatThe twisted pair of WHITE wires are run from theLOW PRESS terminals on the P/L board to a change-over thermostat. The thermostat should be openwhen cold, and closed when hot.

Auxiliary HeatThe YELLOW and WHITE/RED wires, and a ground,should be run to the auxiliary heat relay. Make surethe relay draws no more than .2 amps, or the P/Lboard can be damaged. (Cruisair air handlers withintegrated aux. heat use a triac which can handle upto 20 amps.)

HumidistatA humidistat can be connected to the HI PRESSterminals on the P/L board, and the unit can beprogrammed to control the humidity in the area.Contact the MDC applications department.

21

INSTALLATION GUIDE: Final Inspection

Seawater System• Is the seawater pump properly sized for the system?(See Specification Manual for correct pumpcapacities.)

• Is the pump wired for proper voltage, correct motor

and rotation?

• Is the pump oriented correctly and mounted se-curely?

• Is the centrifugal seawater pump located so as to bebelow the water line at all times?

• Are the inlet and outlet thru-hulls secure, properlysealed and properly oriented?

• Are all seawater hoses double clamped?

• Are the inlet and outlet pipes connected to thecorrect fittings on the tempering unit?

• Are there any loops or dips in the seawater plumb-ing that might cause the system to become airlocked?

• Is the strainer located between the seacock and thepump, and is it correctly oriented?

• Are the appropriate valves open?

Tempering Units• Is the tempering unit mounted securely?

• Are the water connections accessible if it is neces-sary to remove the unit for service later?

• Are condensate drains properly routed to an over-board discharge or sump?

• Is all wiring connected properly?

• Is the balancing flow control the correct size andproperly installed?

• Are the appropriate valves open?

Air Handlers• Are the units securely mounted?

• Are condensate drains properly routed to an over-board discharge or sump?

• If only one condensate drain is used, have any otherdrain holes in the condensate pan been plugged?

• Are the inlet and outlet pipes connected properly?

• Are isolation valves open?

Prior to starting the system, conduct a final inspection, using the following checklist.

Loop Plumbing• Are joints tightened?

• Are joints and tees properly insulated?

• Are pipes individually insulated?

• Are pipes fastened securely to the boat as neededthroughout their length?

• Leak test loop with air and repair any problems.

Air Distribution System• Is there unobstructed airflow from the return air grillto the coil?

• Is there a lint screen or filter in the return air pathwhere it is accessible for regular cleaning?

• Have flexible ducts been pulled tight to removebends and constrictions?

• Are grills and ducts correctly sized for the system?

Controls And Wiring• Is the thermostat sensor or thermistor properlylocated and secured in the return air path and not indirect contact with any metal objects? (For switchassemblies with two sensing bulbs, the large onegoes in the return air path and the small one in thedischarge air path.)

• Are all wiring harnesses properly secured?

• Are wiring connections made, color to color, cor-rectly at terminal strips?

• Are plugs and pins properly aligned and securelyconnected?

• Are all components properly grounded?

• Are proper sized circuit breakers used?

• Are terminal strips located in a dry, safe place andproperly covered?

• Check high voltage wiring.

• Check low voltage wiring.

22

Notes

23

WARNINGDometic Corporation (Dometic) manufacturers of Cruisair, Grunert, MarineAir and Sentry Products, makes the following safety warnings concerningthe application, installation, use and care of its products. Although thesewarnings are extensive, there may be specific hazards which may ariseout of circumstances which we have not outlined herein. Use this as a guide fordeveloping an awareness of potential hazards of all kinds. Such an awarenesswill be a key factor in assuring your SAFETY and comfort.

ELECTRICITY - Many Dometic products operate on 115, 230 or 440 voltAC power. Such voltages can be LETHAL; therefore, the chassis,cabinets, bases, etc., on all components must be grounded together andconnected to the vessel's grounding system. Sparks can occur asswitches, thermostats and relays open and close in the normal operationof the equipment. Since this is the case, ventilating blowers for theremoval of hazardous fumes or vapors should be operated at least 5minutes before and during operation of any Dometic product or group ofDometic products. All electrical connections must be covered andprotected so accidental contact cannot be made by persons using theequipment, as such contact could be LETHAL.

ELECTROLYSIS - Electrical leakage of any component can cause electrolyticdeterioration (electrolysis) of thru-hull components which could result in leakageserious enough to sink a vessel which could result in loss of life. AllDometic components must be kept clean and dry and checked periodicallyfor electrical leakage. If any electrical leakage is detected, the componentshould be replaced or the fault causing the leakage corrected before thecomponent is put back into service.

GAS - CRUISAIR, MARINE AIR and GRUNERT components utilize R134arefrigerant, tetrafluoro-ethane or R404A, R125/R143a/R134 (44%/52%/47%)which are non-toxic, non-flammable gases; however, these gases contain nooxygen and will not support life. Refrigerant gas tends to settle in the lowestareas of the compartment. If you experience a leak, evacuate all personnel, andventilate area. Do not allow open flames in the area of leaks because refrigerantgas, when burned, decomposes into other potentially LETHAL gases.Refrigerant components operate at high pressure and no servicing should beattempted without gloves, long-sleeved clothing and eye protection. Liquidrefrigerant gas can cause severe frost burns to the skin and eyes.

VENTILATION - To cool or heat air, CRUISAIR, MARINE AIR and GRUNERTcomponents are designed to move air through a heat exchanger by a blower or

Warning Revised: 7-6-99

propeller fan. This design necessarily produces a suction on one side ofthe air handling component and a pressure on the other side. Air handlingcomponents must be installed so that the suction-pressure action doesnot: (1) pressurize an area to the extent that structural failure occurswhich could cause harm to occupants or bystanders, or (2) cause asuction or low pressure in an area where hydrogen gas from batteries, rawfuel vapor from fuel tanks, carbon monoxide from operating propulsionengines, power generators or heaters, methane gas from sewage holdingtanks, or any other dangerous gas or vapor could exist. If an air handlingunit is installed in such a manner that allows potentially lethal gases orvapors to be discharged by the air handling unit into the living space, thiscould result in loss of life.

Maximum protection against the introduction of dangerous gases or vapors intoliving spaces can be obtained by providing living spaces which are sealed fromall other spaces by use of airtight bulkheads and decks, etc., and through theintroduction of clean air into the living space. Bear in mind that the advent of airconditioning, whether it be for cooling or for heating, naturally leads to thepractice of closing a living space tightly. Never close all windows and doorsunless auxiliary ventilating systems, which introduce clean outside air into theliving space, are used. Always leave enough window and door openings toprovide adequate ventilation in the event potentially lethal gases or fumes shouldescape from any source.

CONDENSATE - All cooling units produce water condensate when operating onthe cooling cycle. This water must be drained from the cooling unit overboard. Ifcondensate is allowed to drip on a wooden structure, rotting or decay andstructural failure may occur which could result in loss of life. If condensate isallowed to drip on electrical components, deterioration of the electricalcomponents could result in hazardous conditions. When an air conditioningsystem is in operation, condensate drains may be subjected to negativepressure. Always locate condensate drains as far as possible from points whereengine waste and other dangerous gases are exhausted so no such dangerousgases can be drawn into the condensate drains.

WarningNever sleep in a closed area on a boat when any equipment, which functions asa result of the combustion of a volatile fuel, is in operation (such as engines,generators, power plants, or oil-fired heaters, etc.) At any time, the exhaustsystem of such devices could fail, resulting in a build-up of LETHAL gases withinthe closed area.

L-0682

Dometic Environmental CorporationP.O. Box 15299 • Richmond, VA 23227-0699 USAPhone: 804-746-1313 • Facsimile: 804-746-7248

For Sales and Service Calls within Europe and the Middle East, please contact +44 (0) 870 330 6101

Website: www.cruisair.com • Email: sales@cruisair.com