Vermont Casting DVT38S2 Troubleshooting the Gas Control System, SIT Nova 820 Millivolt Valve

Chateau™ Decorative Gas Appliance

Troubleshooting the Gas Control System

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
1.	Spark ignitor will not light	A. Defective or misaligned electrode	Using a match, light pilot. If pilot lights, turn off pilot and
		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)	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 toMaintenance
			Section. If the problem still exists, replace the ignitor
			module box.
2.	Pilot will not stay lit after	A. Defective pilot generator (thermo-	Check pilot flame. Must impinge on thermocouple/ther-
			mopile. NOTE: This pilot burner assembly utilizes both
	carefully following lighting	couple), remote wall switch
			a thermocouple and a thermopile. The thermocouple
	instructions
			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 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.
3.	Pilot burning, no gas to	A. Wall switch or wires defective	Check wall switch and wires for proper connections.
			Jumper wire across terminals at wall switch, if burner
	main 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 generat-	1. Be sure wire connections form thermopile at gas
			valve terminals are tight and thermopile is fully
		ing sufficient millivoltage
			inserted into pilot bracket.
			2. One of the wall switch wires may be grounded. Re-
			move 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 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 opera-	Turn valve knob to “On”, place wall switch to “On”
			millivolt meter should read greater than 150mV. If the
		tor
			reading is okay and the burner does not come on,
			replace the gas valve.
		A. Pilot flame may be too low or	Clean and/or adjust pilot flame for maximum flame
			impingement on thermopile and thermocouple.
		blowing (high) causing the pilot
4.	Frequent pilot outage	safety to drop out
	problem
		B. Possible blockage of the vent	Check the vent terminal for blockage (recycling the flue
		terminal	gases).

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