Williams 3003611, 3003612, 2203611, 2203612 Troubleshooting Gravity Direct Vent Wall Furnace

Troubleshooting Gravity Direct Vent Wall Furnace

SYMPTOM		POSSIBLE		CAUSE
1. Pilot will	not stay lit after	A. Thermocouple		or	gen-
carefully	following	erator	producing		insuffi-
lighting	instructions.	cient	millivoltage.
		B. Loose or dirtythermocou-
		pie or generator connec-
		tions	at gas valve.
		C. Thermocouple or gen-
		erator	defective.

D. Grounded thermostat lead wire (Wall ther- mostat model).

CORRECTIVE ACTION

Check pilot flame - must impinge on thermocou- pie or generator. Be sure thermocouple or generator is fully inserted in bracket. Make sure pilot lighting door is tightly closed.

Clean and/or tighten thermocouple or generator connections at valve.

Check thermocouple with millivolt meter. Should generate approximately 30 millivolts when not con- nected to load. When connected to load, should

generate approximately 14 millivolts; if below 7 millivolts, replace.

Check generator with millivolt meter. Take reading at generator terminals of valve with pilot burning and thermostat contacts closed. Should be 140 millivolts or more.

Remove thermostat lead wires from valve terminals. If pilot now stays lit, trace thermostat wiring circuit for a ground. May be grounded to furnace or gas supply.

2.Pilot burning - no gas to main burner.

3.Burner comes "On" but goes "Off" after operating for no apparent reason.

E. Thermomagnet pilot safety defective.

A.Manual valve not turned to "On" position after lighting pilot.

B.Temperature dial or ther- mostat not turned to a position calling for heat.

C.Plugged burner orifice.

DTemperature dial out of

calibration. (Bulb control model.)

E.Mis-wired or broken ther- mostat wires. Defective

thermostat. 0Nail thermo- stat model.

FPilot generator may not be generating sufficient millivoltage to open valve.

G. Defective valve.

A. Tubes not properly installed.

B. Furnace may be overrated.

g21--

Replace gas valve after above is checked out.

Turn gas valve knob to "On" position.

Set temperature dial or thermostat to a position call- irtg for heat.

Check - clean or replace.

See valve manufacturer's instructions.

Check connections at valve terminals. Jumper across thermostat terminals on valve - if valve

operates check thermostat wires.

See 1A above.

Replace.

Check vent tube and air inlet tube. Follow installa- tion instructions. Be sure joints are tight and both tubes are in place. Use only tubes furnished. Do not extend tubes beyond original length.

Check for high pressure at valve - see rating plate for specified minimax supply pressure. Check burner orifice.

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