33
20306759
Radiance
®
Direct Vent Gas Heater
SIT NOVA 820 MILLIVOLT VALVE
NOTE: Before trouble shooting the gas control system, be sure external gas shut off is in the “On" position.
Symptom
Possible Causes
Corrective Action
Spark Ignitor will not
light
1. Defective or mis-
aligned electrode at
pilot
1. 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.
2. Defective ignitor
(push button)
2. 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.
Pilot will not stay
lit after carefully
following lighting
instructions
1. Defective pilot gener-
ator (thermocouple),
remote wall switch
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.
2. Defective automatic
valve
2. 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.
Pilot burning, no
gas to main burner
1. Wall switch or wires
defective
1. Check wall switch and wires for proper connections. Jumper wire across termi-
nals 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.
2. Thermopile may not
be generating suffi
-
cient millivoltage
•
Be sure wire connections form thermopile at gas valve terminals are tight
and thermopile is fully inserted into pilot bracket.
•
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 stove or gas supply.
•
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.
3. Plugged burner
orifice
3. Check burner orifices for debris and remove.
4. Defective automatic
valve operator
4. 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.
Frequent pilot out-
age problem
1. Pilot flame may be
too low or blowing
(high) causing the
pilot safety
to drop out
1. Clean and/or adjust pilot flame for maximum flame impingement on thermopile
and thermocouple.
2. Possible blockage of
the vent terminal
2. Check the vent terminal for blockage (recycling the flue gases)
OPERATING INSTRUCTIONS
TROUBLESHOOTING THE GAS CONTROL SYSTEM (RADVT MODELS)
