Residential Gas – Honeywell Valve - Thermopile Powered

Series 300/301

Atmospheric Vented

Category IStatus LED

Wrap-around Filter

• Introduction

• Installation

• Operation

• Service

Gas Valve/Thermostat

Spark Igniter Button

LED StatusLight

Status Codes

Thermopile

Powered

Gas Valve/Thermostat

Propane Gas Valve/Thermostat Color Coding

Installation

Installation – Gas Supply

Gas Maximum Supply Press.

Manifold Gas Press.

Natural 10.5 In WC 5.0 In WC

Propane 13.0 In WC 10.0 In WC

Installation - Piping

Installation – Combustion Air

• 12.5 Cubic Feet of Air Per 1000 Btu

1,000BTU1,000BTU +

10 CU.FT.

COMB.AIR

10 CU.FT.

COMB.AIR

2.5 CU.FT.

EXCESSAIR

2.5 CU.FT.

EXCESSAIR

• Operation

Operation - Thermopile Powered

A grouping of thermocouples into one housing results in a “Thermopile” or “Generator”

• Heat on the thermopile, generates 750 to 850 milli- volts (.750VDC) – open circuit.

• When heated and connected to the gas valve, ours generates 350 or more mV - closed circuit.

Operation - Lighting the Pilot

Note This Comment

Note this

comment

Operation – Lighting the Pilot

The pilot cannot be relit if this steady LED light is still ON. The thermopile must cool to automatically reset the control.

Operation – Lighting the Pilot

• Status Indicator– Blinking once every 3 seconds = pilot knob

may be released and normal operation in HEAT mode.

– Solid On – control has been turned Off – thermopile cooling

– 2 to 8 flashes every 3 seconds – error codes

Operation - Temperature Adjustment

Dial Approx. Temp ° F

VAC 55

HOT 120

VERY HOT

155

120°F is the recommended setting

Review Questions

1. Natural Gas – maximum gas supply pressure?

10.5 Inches WC

Review Questions

2. Since these products get combustion air directly from outdoors, indoor air supply does not matter?

They do NOT use air directly from outdoors. They use room air for combustion and therefore room air quality and quantity is very important.

Review Questions

3. Thermopile – This is a misspelling of thermocouple?

No – a thermopile is like a grouping of thermocouples into one housing. This results in a much stronger DC milli-voltage output from the heated end of the thermopile to the gas valve.

Review Questions

4.Thermopiles receive electrical power from a transformer?

No – pilot heat on the end of the thermopile generates electricity – millivolts. A maximum of 750 MV Vs a thermocouple which normally has a maximum output of 30MV.

Review Questions

5. Millivolts are AC or DC?

Direct Current

Review Questions

6. When I see the pilot light through the sight glass, I can release the pilot knob?No, you must wait for the LED to flash indicating the milli-voltage from the thermopile circuit has reached an adequate level to power the gas valve/thermostat control functions.

Service

Service - Combustion Chamber

Service - Burner Assembly

Service - Supply Gas Pressure Test

Burner Off – Static Pressure

9.85 In W.C.

Burner On – Dynamic Pressure

8.90 In W.C.

(Natural Gas)

Service – Manifold Gas Pressure

See Gas Valve Label Or Model and Rating Plate For Proper

Reading

Pressure Test Fittings

Service - LED Diagnostic Codes

If you have to reset the thermal switch (TCO), always check for flammable vapors or clean the filter and flame trap before

relighting.

Service

Service – Connections Check

Igniter Wire

From Thermopi

le(White)

From Thermal Switch (Red)

Manifold Press. Tap

Igniter Button

Service - Wrap Around Air Filter

Wrap Around Air Filter Must Be Kept Clean

Service - Thermopile Powered

A grouping of thermocouples into one housing results in a “Thermopile” or “Generator”

• Heat on the thermopile, generates 750 to 850 milli- volts (.750VDC) – open circuit.

• When heated and connected to gas valve, ours generates 350 or more mV - closed circuit.

Disconnecting Thermopile

Disconnect wires from gas valve/thermostat

Service - Thermopile Check –Open Circuit

Knob held in to

sustain gas to pilot

Multimeter testing of

thermopile leads

Generating .797VDC or

797 millivolt

From thermopile

From thermal switch

Service - Thermopile Check –Closed Circuit

Generating .353VDC or 353.4 millivolt

Thermopile circuit

leads are connected

to gas valve

Pilot is lit

Multi-meter leads

inserted into

thermopile circuit

connections

Service - Thermopile Check –Closed Circuit

.658VDC or 658 mV- well in excess of

the minimum 350mV

Multi-meter test lead to

thermostat connection

(white) and 2nd lead to thermal

switch.

Pilot is lit

2nd closed circuit test method

Red – from

thermal

switch

Review Questions

9. I can not relight the pilot! Most likely reasons?

• Thermopile still hot – wait for LED to go out,

• open thermal switch (TCO),

• plugged filter,

• plugged flame-trap.

Review Questions

10. My multimeter says that the thermopile is generating nearly 30 milli-volts DC. Why won’t my pilot light.

30mv is a thermocouple reading value.

• Check multimeter setting,

• poor flame impingement on thermopile,

• faulty thermopile.

Review Questions

11. My shower time has decreased significantly. Why?

A 40 gallon model set at 140°F was removed and a 40 gallon model set at 120° was installed.

Atmospheric Vented, Residential Gas – Honeywell Valve -

Thermopile PoweredSeries 300/301

• www.hotwater.com for product specs and installation manuals.