Williams 2001622 - Troubleshooting

Troubleshooting
Symptom Possible Causes Corrective Action
1.
Pilot will not stay lit after
carefully following lighting
instructions.
A. Generator producing insufficient millivolts.
Check pilot flame. It must impinge on the
generator. Be sure generator is fully inserted in
bracket.
B.
Loose or dirty generator connections at gas
valve.
Clean and/or tighten connections at valve.
C. Generator defective.
Check 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 thermostat wires from valve terminals.
If pilot now stays lit, trace thermostat wiring
circuit for a ground. May be grounded to
furnace, gas supply, nails or staples.
E. Defective valve. Replace 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 thermostat to a position calling for heat.
B. Plugged burner orifice. Clean or replace.
C.
Improperly wired or broken thermostat wires.
Defective thermostat.
Check connections at valve terminals. If valve
operates, check thermostat wires.
D.
Pilot generator may not be generating sufficient
millivoltage to open valve.
See 1A and 1C above.
E. Defective valve. Replace.
3.
Furnace operates but turns
"OFF" before room temperature
is attained.
A. Thermostat location.
Check thermostat location. It should not be in
the path of warm air discharge from furnace,
near a lamp, or above a T.V. or stereo.
B. Defective thermostat. Check thermostat calibration or replace.
4. Furnace not producing sufficient
heat.
A.
Furnace may be too small for space being
heated.
Check heat sizing calculations.
B. Furnace 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.
Furnace 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.
C. Defective thermostat.
Verify thermostat temperature reading or
replace.
D. Valve stuck open. Replace valve.
6. Pilot outage. A.
Pilot flame may be 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 movement areas.
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