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Troubleshooting the Gas Control System
NOTE: Before trouble shooting the gas control system, be sure external gas shut off is in the "On" position.
Symptom
1. Spark ignitor will not light
2. Pilot will not stay lit after carefully fol-
lowing lighting instructions
3. Pilot burning, no gas to main burner
4. Frequent pilot outage problem
3-90-693831
Hearth and Home Technolgies • Oxford Direct Vent Installation Manual_R6 • 08/17
SIT NOVA 820 MILLIVOLT VALVE
Possible Cause
A. Defective or misaligned electrode at
pilot.
B. Defective ignitor (Push Button)
A. Defective pilot generator (thermocou-
ple), remote wall switch
B. Defective automatic valve
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. Possible blockage of the vent terminal
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.
With the control knob in the pilot position,
push the control knob all the way and hold.
Check for spark at electrode and pilot. If no
spark to pilot, and electrode wire is properly
connected, replace the battery in the ignitor
module and try again. Refer to Maintenance
Section. If the problem still exists, replace the
ignitor module box.
Check pilot flame. Must impinge on thermo-
couple/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 im-
pingement on thermopile and thermocouple.
Turn valve knob to "Pilot". Maintain flow to
pilot; millivolt meter 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.
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 form thermopile
at gas valve terminals are tight and ther-
mopile is fully inserted into pilot bracket.
2. One of the wall switch wires may be
grounded. Remove wall switch wires
form 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 milli-
volts (minimum 150) while holding valve
knob depressed 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
150mV. 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 ther-
mocouple.
Check the vent terminal for blockage (recy-
cling the flue gases).
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