Monessen Hearth 36CDVXTRN Troubleshooting the Gas Control System, SIT NOVA 820 MILLIVOLT VALVE

CDVX Series Direct Vent Gas Fireplace

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.

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
	electrode at pilot.	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.
	B. Defective ignitor (Push Button)	Push Piezo Ignitor Button. Check for spark at
		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 thermo-
carefully following lighting	(thermocouple), remote wall	couple/thermopile. Note: this pilot burner assem-
instructions.	switch.	bly 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 fully
	millivoltage.	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)

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