Williams wall heater troubleshooting

The American manufacturer Williams Heater Co. produces furnaces and heaters from the 1930’s. Now we can confidently say that the company offers a great range of products for every situation. In particular, wall heaters Williams provide rapid heat with high efficiency in electric, natural gas or propane. If Williams heaters are broken, please refer to the troubleshooting table below.

1. Pilot will not stay lit after following lighting instructions.A. Generator producing insufficient mill volts.Check pilot flame - it must impinge on the generator from 1/4 to 3/8-inches . Be sure the thermocouple is fully inserted in its bracket.
B. Loose or dirty generator connections at gas valve.Clean and/or tighten the connections at the valve.
C. Generator defective.Check the generator with millivolt meter. Take reading at the generator terminals of the valve with the valve placed in "Pilot" position. Disconnect the thermostat wires. The millivolt reading should be 450 millivolts or more.
D. Grounded thermostat wire.Remove the thermostat wires from the valve terminals. If the pilot now stays lit. trace the thermostat wiring circuit for a ground. May be grounded to heater, gas supply, nails or staples.
E. Defective valve.Replace the gas valve after above is verified.
2. Pilot burning - no gas to the main burner.A. Thermostat not turned to a position calling for heat.Set the thermostat to a position calling for heat.
B. Plugged burner orifice.Clean or replace.
C. Improperly wired or broken thermostat wires.Check the connections at valve terminals. If valve operates, check the thermostat wires.
Defective thermostat.
D. Pilot generator may not be generating sufficient mill voltage to open valve.See 1Aand 1C above.
E. Defective valve.Replace.
3. Burner comes "ON" but goes OFF before blower turns ON.A. Thermostat location.Check the thermostat location. It should not be in the path of warm air discharge from heater, near a lamp, or above a T.V. or stereo.
B. Defective thermostat.Check the thermostat calibration or replace.
4. Heater notA. Heater may be too small for space being heated.Check heat sizing calculations.
producing sufficient heat.B. Heater not burning at full rate.Check for low gas pressure at gas valve. It should be 4 inches W.C. for Natural Gas; 10.5 inches W.C. for L.P.G. Check for blocked burner orifice.
5. Heater operates, but will not shut off after room temperature is attained.A. Thermostat wiring defective.Thermostat lead wires may be shorted together, caused by a nail or staple. Check by removing thermostat leads from valve terminals.
B. Thermostat location.Check thermostat location. If on an outside wall, or there is a hole in the wall behind thermostat, cold air may be coming in contact with the thermostat. Relocate the thermostat or plug the hole.
C. Defective thermostat.Verify thermostat temperature reading or replace.
D. Valve stuck open.Replace valve.
6. Pilot outage.A. Pilot flame may be too low or blowing (high), causing pilot to drop out.Adjust pilot flame. Pilot orifice may be plugged (Check for spider webs or other material).
B. Drafts or drafty areas.Check for doorway and high air movement areas.
7. Main burner will not stay on.A. Blockage in vent pipe.Checks vent pipe for blockage, such as bird nests, twigs, leaves, etc.
B. Thermostat location.Check thermostat location - if on an outside wall or there is a hole in wall behind the thermostat causing cold air to contact the thermostat, relocate the thermostat or plug the hole. Check that the vent cap is properly installed, and not placed too far down on the vent pipe. Cap must be the same manufacturer as the vent.
C. Restriction in vent system caused by offsets.All type "B" vents shall extend in a vertical direction with no more than two offsets not exceeding 45 degrees. Any angle greater than 45 degrees from vertical is considered horizontal. Any offsets used should be as far above the draft hood as possible to allow venting to begin before any restriction is encountered. The use of too many offsets may also prevent proper venting.
D. Incorrect vent pipe.Use listed B/W type vent pipe. DO NOT use transite or any other type of ceramic pipe for venting. DO NOT use single wall pipe. When venting into a masonry chimney, the chimney must be properly lined and sized for this gas heater. The use of type "B“ or flexible chimney liner is recommended.
E. Loose connections on the vent safety wiring harness.Check the connection on both the switch and the gas valve. Tighten if necessary.
8. Abnormal operation.A. Delayed ignition - pilot flame may be too low.Adjust pilot flame.
B. Expansion noise, ticking.Heater may be distorted by being vented through an uneven opening. A restricted vent may create expansion noise.
C. Combustible gas spillage.Check vent system for a blocked flue, excessive down draft (wind) or negative pressure in room caused by ventilating fan or a fire in a fireplace.
D. Excessive flame roll- out.Heater is possibly overrated - check for high gas pressure at gas valve (see 4B).
E. Burner is over-fired.Check the manifold gas pressure. Check the rate, this appliance is manufactured for elevations up to 2,000 feet. It must be derated for operation above 2,000 feet.
F. Yellow burner flame.Check burner for obstructions. Install new burner and pilot orifices.
G. Yellow pilot flame.Remove pilot orifice, check and clean.
9. Noisy blower.A. Housing rattling.Tighten blower screws.
B. Blower dirty.Clean blower wheel.
C. Blower wheel bent.Straighten or replace.
10. Blower does not run.A. Fan switch not set.Select fan speed.
B. Check bearings.Add oil as outlined in "Blower Accessory Instructions".