Troubleshooting Gas Control (Sit 630) - Vermont Castings A232 Installation Instructions & Homeowner's Manual

TROUBLE SHOOTING THE GAS CONTROL SYSTEM
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.
SYMPTOM
1. Spark ignitor will not light
2. Pilot will not stay lit after
carefully following lighting
instructions.
3. Pilot burning, no gas to
burner, Valve knob "ON",
Wall Switch "ON".
4. Frequent pilot flare outage
problem.
SIT NOVA 820 MILLIVOLT VALVE
POSSIBLE CAUSES
A. Defective or misaligned
electrode at pilot.
B. Defective ignitor (Push Button)
A. Defective pilot generator
(thermocouple), remote wall
switch.
B. Defective automatic valve
operator.
A. Wall switch or wires
defective.
B. Thermopile may not be
generating sufficient
millivoltage.
C. Plugged burner orifice.
D. Defective automatic valve
operator.
A. Pilot flame may be too low
or blowing (high) causing the
pilot safety to drop out.
B. Vent safety shutdown.
CORRECTIVE ACTION
Using a match, light pilot. If pilot lights, turn off pilot and
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.
Push Piezo Ignitor Button. Check for spark at electrode and
pilot. If no spark to pilot, and electrode wire is properly
connected, replace ignitor.
1. Check pilot flame. Must impinge on thermocouple/
thermopile. Note: this pilot burner assembly utilizes both
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.
Turn valve knob to "Pilot". Maintain flow to pilot; millivolt
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.
Check wall switch and wires for proper connections. Jumper
wire across terminals at wall switch, if burner comes 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.
1. Be sure wire connections from thermopile at gas valve
terminals are tight and thermopile is fully inserted into pilot
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
fireplace or gas supply.
3. Check thermopile with millivolt meter. Take reading at
thermopile terminals of gas valve. Should read 250-300
millivolts (minimum 150) while holding valve knob de-
pressed in pilot position and wall switch "Off". Replace
faulty thermopile if reading is below specified minimum.
Check burner orifices for debris and remove.
Turn valve knob to "On", place wall switch to "On" millivolt
meter should read greater than 100 mV. If the reading is
okay and the burner does not come on, replace the gas
valve.
Clean and/or adjust pilot flame for maximum flame
impingement on thermopile and thermocouple.
Check the vent system for blockage. Check all connections
on vent safety switch.
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