Vermont Casting D232 SIT NOVA 820 MILLIVOLT VALVE, Symptom, Possible Causes, Corrective Action

TROUBLE SHOOTING 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.

WARNING: BEFORE DOING ANY GAS CONTROL SERVICE WORK, REMOVE GLASS FRONT.

	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 pilot and
		electrode 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)	Push Piezo Ignitor Button. Check for spark at electrode and
			pilot. If no spark to pilot, and electrode wire is properly
			connected, replace ignitor.
2. Pilot will not stay lit after		A. Defective pilot generator	1. Check pilot flame. Must impinge on thermocouple/
	carefully following lighting	(thermocouple), remote wall	thermopile. Note: this pilot burner assembly utilizes both
	instructions.	switch.	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
		operator.	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	Check wall switch and wires for proper connections. Jumper
	burner.		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 gas valve
		generating sufficient	terminals are tight and thermopile is fully inserted into pilot
		millivoltage.	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.
		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" millivolt
		operator.	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 flue gases)
		terminal.

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