Trouble shooting the gas control system, Symptom possible causes corrective action, Sit 820 millivolt valve – Vermont Casting IRHEDV32 User Manual

Page 13

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SYMPTOM

POSSIBLE CAUSES

CORRECTIVE ACTION

1. Spark ignitor will not light

A. Defective or misaligned

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

electrode at pilot.

push the red button again. If pilot will not light - check gap
at electrode and pilot-should be 1/8" to have a strong spark.

B. Defective ignitor (Push Button)

Push Piezo Ignitor Button. Check for spark at electrode and

pilot. If no spark to pilot, and electrode wire is properly

connected, replace ignitor.

2. Pilot will not stay lit after

A. Defective pilot generator

1. Check pilot flame. Must impinge on thermocouple/

carefully following lighting

(thermocouple), remote wall

thermopile. Note: this pilot burner assembly utilizes both

instructions.

switch.

a thermocouple and a thermopile. The thermocouple
operates the main valve operation (On and Off). Clean
and or adjust pilot for maximum flame impingement on
thermopile and thermocouple.

B. Defective automatic valve

Turn valve knob to "Pilot". Maintain flow to pilot; millivolt

operator.

meter should read greater than 10 mV. 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.

3. Pilot burning, no gas to

A. Wall switch or wires

Check wall switch and wires for proper connections. Jumper

burner, Valve knob "ON",

defective.

wire across terminals at wall switch, if burner comes on,

Wall Switch "ON".

replace defective wall switch. If okay, jumper wires across
wall switch wires at valve, if burner comes on, wires are
faulty or connections are bad.

B. Thermopile may not be

1. Be sure wire connections from thermopile at gas valve

generating sufficient

terminals are tight and thermopile is fully inserted into pilot

millivoltage.

bracket.

2. One of the wall switch wires may be grounded. Remove

wall switch wires from valve terminals if pilot now stays lit,
trace wall switch wiring for ground. May be grounded to
appliance or gas supply.

3. Check thermopile with millivolt meter. Take reading at

thermopile terminals of gas valve. Should read 325 milli-
volts minimum while holding valve knob depressed in
pilot position and wall 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 valve knob to "On", place wall switch to "On" millivolt

operator.

meter should read greater than 100 mV. If the reading is
okay and the burner does not come on, replace the gas
valve.

4. Frequent pilot outage

A. Pilot flame may be too low

Clean and/or adjust pilot flame for maximum flame

problem.

or blowing (high) causing the

impingement on thermopile and thermocouple.

pilot safety to drop out.

B. Possible leak in liner or seals.

Check the venting for leaks or blockage.

TROUBLE SHOOTING THE GAS CONTROL SYSTEM

SIT 820 MILLIVOLT VALVE

Note: Before trouble shooting the gas control system, be sure external gas shut off is in the "On" position.

WARNING: BEFORE DOING ANY GAS CONTROL SERVICE WORK, REMOVE GLASS FRONT.

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