Troubleshooting - Williams 2001622 Installation & Operating Instruction Manual

Symptom
1. Pilot will not stay lit after
carefully following lighting
instructions.
2. Pilot burning - no gas to the
main burner.
3. Furnace operates but turns
"OFF" before room temperature
is attained.
4. Furnace not producing sufficient
heat.
5. Furnace operates, but will not
shut off after room temperature
is attained.
6. Pilot outage.

Troubleshooting

Possible Causes
A. Generator producing insufficient millivolts.
B. Loose or dirty generator connections at gas
valve.
C. Generator defective.
D. Grounded thermostat wire.
E. Defective valve.
A. Thermostat not turned to a position calling for
heat.
B. Plugged burner orifice.
C. Improperly wired or broken thermostat wires.
Defective thermostat.
D. Pilot generator may not be generating sufficient
millivoltage to open valve.
E. Defective valve.
A. Thermostat location.
B. Defective thermostat.
A. Furnace may be too small for space being
heated.
B. Furnace not burning at full rate.
A. Thermostat wiring defective.
B. Thermostat location.
C. Defective thermostat.
D. Valve stuck open.
A. Pilot flame may be low or blowing (high),
causing pilot to drop out.
B. Drafts or drafty areas.
Check pilot flame. It must impinge on the
generator. Be sure generator is fully inserted in
bracket.
Clean and/or tighten connections at valve.
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.
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.
Replace gas valve after above is verified.
Set thermostat to a position calling for heat.
Clean or replace.
Check connections at valve terminals. If valve
operates, check thermostat wires.
See 1A and 1C above.
Replace.
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.
Check thermostat calibration or replace.
Check heat sizing calculations.
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.
Thermostat lead wires may be shorted together,
caused by a nail or staple. Check by removing
thermostat leads from valve terminals.
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.
Verify thermostat temperature reading or
replace.
Replace valve.
Adjust pilot flame. Pilot orifice may be plugged
(check for spider webs or other material).
Check for doorway and high movement areas.
12
Corrective Action