Heatiator NB4842MI Troubleshooting, A. Standing Pilot Ignition System, Symptom, Possible Causes

14 Troubleshooting

With proper installation, operation and maintenance your gas appliance will provide years of trouble-free service. If you do experience a problem, this troubleshooting guide will assist a qualified service person in the diagnosis of a problem and the corrective action to be taken. This troubleshooting guide can only be used by a qualified service technician.

A. Standing Pilot Ignition System

	Symptom		Possible Causes	Corrective Actions
1.	After repeated triggering	A.	Defective ignitor.	Check the spark at the electrode and pilot. If there is no spark and the
	of the red or black piezo			electrode wire is properly connected, replace the ignitor.
	ignitor button, the spark
		B.	Defective pilot or	Using a match, light the pilot. If the pilot lights, turn off the pilot and trigger
	ignitor will not light the
			misaligned electrode	the red or black piezo ignitor button again. If the pilot lights, an improper
	pilot.
			(spark at electrode).	gas/air mixture caused the bad lighting and a longer purge period is
				recommended. If the pilot will not light, ensure the gap at the electrode and
				pilot is 1/8 in. to have a strong spark. If the gap is OK, replace the pilot.
		C.	No gas or low gas	Check the remote shut-off valves from the appliance. There is usually a
			pressure.	valve near the gas main. There can be more than one valve between the
				appliance and the main.
		D.	No LP in tank.	Check the LP (propane) tank. You may be out of fuel.
2.	The pilot will not stay lit	A.	Defective thermocouple.	Check that the pilot flame impinges on the thermocouple. Clean and/or
	after carefully following			adjust the pilot for maximum flame impingement.
	the lighting instructions			Ensure that the thermocouple connection at the gas valve is fully inserted
				and tight (hand tighten plus 1/4 turn).
				Disconnect the thermocouple from the valve, place one millivolt meter lead
				wire on the tip of the thermocouple and the other meter lead wire on the
				thermocouple copper lead. Start the pilot and hold the valve knob in. If the
				millivolt reading is less than 15mV, replace the thermocouple.
		B.	Defective valve.	If the thermocouple is producing more than 15 millivolts, replace faulty valve.
3.	The pilot is burning, there	A.	ON/OFF switch or wires	Check the ON/OFF switch and wires for proper connections. Place the
	is no gas burning, the		are defective.	jumper wires across the terminals at the switch. If the burner comes on,
	valve knob is in the ON			replace the defective switch. If the switch is OK, place the jumper wires
	position, and the ON/			across the switch wires at the gas valve. If the burner comes on, the wires
	OFF switch is in the ON			are faulty or connections are bad.
	position.	B.	Thermopile may not be	If the pilot flame is not close enough physically to the thermopile, adjust the
			generating sufficient	pilot flame.
			millivoltage.	Be sure the wire connections from the thermopile at the gas valve terminals
				are tight and that the thermopile is fully inserted into the pilot bracket.
				Check the thermopile with a millivolt meter. Take the reading at TH-TP&TP
				terminals of the gas valve. The meter should read 325 millivolts minimum
				while holding the valve knob depressed in the pilot position, with the pilot lit,
				and the ON/OFF switch in the OFF position. Replace the faulty thermopile of
				the reading is below the specified minimum.
				With the pilot in the ON position, disconnect the thermopile leads from
				the valve. Take a reading at the thermopile leads. The reading should be
				325 millivolts minimum. Replace the thermopile if the reading is below the
				minimum.
		C.	Defective valve.	Turn the valve knob to the ON position. Place the ON/OFF switch in the ON
				position. Check the millivolt meter at the thermopile terminals. The millivolt
				meter should read greater than 125mV. If the reading is acceptable, and if
				the burner does not come on, replace the gas valve.
		D.	Plugged burner orifice.	Check the burner orifice for stoppage. Remove stoppage.
		E.	Wall switch or wires are	Follow the corrective action in Symptom and Possible Cause 1.A. above.
			defective.	Check the switch and wiring. Replace where defective.

34 Heatilator • Novus BV-Mesh • 4031-553 Rev F • 11/07