Vermont Casting 3356 4409 410, 3340 Radiance Natural Vent Gas Heater, Symptom, Possible Causes

Models: 3356 4409 410 3340 3355 3349

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SYMPTOM

Radiance Natural Vent Gas Heater

Troubleshooting / Honeywell #8420 Gas Control System

NOTE: Before troubleshooting the gas control system, be sure the external gas shutoff is in the “ON” position.

WARNING: REMOVE THE GLASS PANEL BEFORE PERFORMING ANY GAS CONTROL SERVICE WORK.

SYMPTOM

POSSIBLE CAUSES

CORRECTIVE ACTION

 

1.

Spark ignitor will

A. Defective or misaligned

Using a match, light [ilot. If pilot lights, turn off pilot and

 

 

not light

electrode at the pilot

push the ignitor button again. If pilot will not light, check

 

 

 

 

gap at electrode and pilot - it should be 1/8” to have a

 

 

 

 

strong spark.

 

 

 

B. Defective ignitor (push

Push piezo ignitor button. Check for spark at electrode

 

 

 

 

button)

and pilot. If there is no spark at the pilot, and electrode

 

 

 

 

wire is properly connected, replace ignitor.

 

2.

Pilot will not stay lit

A. Defective pilot generator

Check pilot flame. It must impinge on the thermocouple

 

 

after carefully

(thermocouple)

or thermopile. NOTE: This pilot burner assembly uses

 

 

following the

 

both a thermocouple adn a thermopile. The thermo-

 

 

lighting instructions

 

couple operates the pilot flame. Tighten the thermo-

 

 

 

 

couple. The thermopile operates the main valve. (ON

 

 

 

 

and OFF) Clean and/or adjust pilot for maximum flame

 

 

 

 

impingement on thermocouple and thermopile.

 

 

 

B. Defective automatic valve

Turn valve knob to “Pilot”. Maintain flow to pilot; millivolt

 

 

 

operator

mete should read greater than 10mV. If the reading is

 

 

 

 

okay and the pilot does not stay on, replace the gas

 

 

 

 

valve. NOTE: An interrupter block (not supplied) must

 

 

 

 

be used to conduct this test.

 

 

 

C.Defective safety switch

Check the continuity accross the safety limit switch with

 

 

 

 

the unit cold. If there is no continuity, the safety switch

 

 

 

 

needs to be replaced.

 

3. Pilot lights, no gas

A. Remote switch or wires

Check rocker switch and wires for proper connection

 

 

 

to burner, valve

defective

Use jumper wires across terminals at rocker switch. If

 

 

knob ON, remote

 

burner lights, replace rocker switch. If okay, use jumper

 

 

switch (rocker

 

wires across rocker switch wires at the valve. If burner

 

 

switch) ON

 

lights, wires are faulty or connections are bad.

 

 

 

B. Thermopile may not gen-

1. Be sure wire connecitons from thermopile at gas

 

 

 

ate sufficient voltage

valve terminals are tight and thermopile is fully inserted

 

 

 

 

into pilot bracket.

 

 

 

 

2. One of the rocker switch wires may be grounded

 

 

 

 

Remove rocker switch wire form valve termianls. If

 

 

 

 

burner now stays lit, trace rocker switch wiring from

 

 

 

 

ground. It may be grounded to the appliance of the

 

 

 

 

gas supply line.

 

 

 

 

3. Check the thermopile with a millivolt meter. Take

 

 

 

 

reading at thermopile (“TP” and “TP/TH”) terminals of

 

 

 

 

gas valve. Should read 325 millivolts minimum while

 

 

 

 

holding valve knob depressed in PILOT position and

 

 

 

 

with rocker switch OFF. Replace faulty thermopile if

 

 

 

 

reading is below specified minimum.

 

 

 

C. Plugged burner orifice

Check burner orifices for debris, and remove.

 

 

 

 

D. Defective automatic valve

Turn knob to ON, place rocker switch to ON. Millivolt

 

 

 

operator

meter should read greater than 10mV. If the reading is

 

 

 

 

okay and the burner does not light, replace the valve.

 

4. Frequent pilot

A. Pilot flame may be too low

Clean and/or adjust pilot flame for maximum flame

 

 

outage

or high, (blowing or lifting).

impingement on thermocouple and thermopile.

 

 

 

causing the pilot to drop out

 

 

 

 

 

B. Possible blockage of the

Check the vent termianl for blockage.

 

 

 

vent terminal

 

 

 

 

 

 

 

 

 

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20004409

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Vermont Casting 3356 4409 410 Radiance Natural Vent Gas Heater, Symptom, Possible Causes, Corrective Action, 20004409