Vermont Casting SDV30 manual Troubleshooting / Honeywell #8420 Gas Control System

Stardance Direct Vent/Natural Vent Gas Heater

Troubleshooting / Honeywell #8420 Gas Control System

NOTE: Before troubleshooting the gas control system, be sure the external gas shutoff is in the “ON” position.

WARNING: REMOVE THE GLASS PANEL BEFORE PERFORMING ANY GAS CONTROL SERVICE WORK.

	SYMPTOM	POSSIBLE CAUSES	CORRECTIVE ACTION
1.	Spark ignitor will not	A. Defective or misaligned elec-	Using a match, light pilot. If pilot lights, turn off pilot
	light	trode at the pilot	and push the ignitor button again. If pilot will not light,
			check gap at electrode and pilot - it should be 1/8” to
			have a strong spark.
		B. Defective ignitor (push button)	Push piezo ignitor button. Check for spark at elec-
			trode and pilot. If there is no spark at the pilot, and
			electrode wire is properly connected, replace ignitor.
		A. Defective pilot generator (ther-	Check pilot flame. It must impinge on the thermo-
2. Pilot will not stay lit		mocouple)	couple or thermopile. NOTE: This pilot burner as-
	after carefully fol-		sembly uses both a thermocouple and a thermopile.
	lowing the lighting		The thermocouple operates the pilot flame. Tighten
	instructions		the thermocouple. The thermopile operates the main
			valve (ON and OFF). Clean and/or adjust pilot for
			maximum flame impingement on thermocouple and
			thermopile.
		B. Defective automatic valve op-	Turn valve knob to ‘Pilot’. Maintain flow to pilot; mil-
		erator	livolt meter should read greater than 10mV. If the
			reading is okay and the pilot does not stay on, re-
			place the gas valve. NOTE: An interrupter block (not
			supplied) must be used to conduct this test.
3.	Pilot lights, no gas to	A. Remote switch or wires defec-	Check rocker switch and wires for proper connection.
	burner, valve knob	tive	Use jumper wires across terminals at rocker switch.
	ON, remote switch		If burner lights, replace rocker switch. If okay, use
	(rocker switch) ON		jumper wires across rocker switch wires at the valve;
			if burner lights, wires are faulty or connections are
			bad.
		B. Thermopile may not generate	1. Be sure wire connections from thermopile at gas
		sufficient voltage	valve terminals are tight and thermopile is fully
			inserted into pilot bracket.
			2. One of the rocker switch wires may be grounded.
			Remove rocker switch wires from valve terminals.
			If burner now stays lit, trace rocker switch wiring
			from ground. It may be grounded to the appliance
			or the gas supply line.
			3. Check the thermopile with a millivolt meter. Take
			reading at thermopile (“TP” and “TP/TH”) terminals
			of gas valve. Should read 325 millivolts minimum
			while holding valve knob depressed in PILOT po-
			sition and with rocker 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 op-	Turn knob to ON, place rocker switch to ON, millivolt
		erator	meter should read greater than 10 mV. If the read-
			ing is okay and the burner does not light, replace the
			valve.
4. Frequent pilot out-		A. Pilot flame may be too low or	Clean and/or adjust pilot flame for maximum flame
	age	high, (blowing or lifting), caus-	impingement on thermocouple and thermopile.
		ing the pilot to drop out
		B. Possible blockage of the vent	Check the vent terminal for blockage.
		terminal