36
Vermont Castings, Majestic Products DVRT36/ 39/ 43
10002428
Troubleshooting the Gas Control System
Note: Before trouble shooting the gas control system, be sure external gas shut off is in the “ON” position.
SIT NOVA 820 MILLIVOLT VALVE
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
electrode at pilot
pilot and push the red button again. If pilot will not
light, check gap at electrode and pilot; it should be
1/8 in. to have a strong spark.
B. Defective ignitor
Push Piezo Ignitor Button. Check for spark at
(Push Button)
electrode and pilot. If no spark to pilot, and elec-
trode wire is properly connected, replace ignitor.
2. Pilot will not stay lit after
A. Defective pilot generator
Check pilot flame. Must impinge on thermocouple/
carefully following lighting
(thermocouple); remote
thermopile. NOTE: This pilot burner assembly
instructions.
wall switch
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.
B. Defective automatic valve
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.
3. Pilot burning; no gas to
A. Wall switch or wires defective
Check wall switch and wires for proper connec-
main burner
tions. 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.
B. Thermopile may not be
1. Be sure wire connections from thermopile at
generating sufficient
gas valve terminals are tight and thermopile is
millivoltage
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 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.”
operator
Millivolt 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 blockage of the vent
Check the vent terminal for blockage (recycling the
terminal
flue gases).
WARNING: BEFORE DOING ANY GAS CONTROL SERVICE WORK, REMOVE GLASS FRONT.
