Williams 2001622A Owner's Manual page 30

Troubleshooting
SYMPTOM
5. Heater operates,
but will not shut off
after room
temperature is
attained.
6. Pilot outage.
7. Main burner will not
stay on.
30
POSSIBLE CAUSE
A. Thermostat wiring
defective.
B. Thermostat location.
C. Defective thermostat.
D. Valve stuck open.
A. Pilot flame may be
too low or blowing
(high), causing pilot
to drop out.
B. Drafts or drafty areas.
A. Blockage in vent pipe.
B. Thermostat location.
C. Restriction in vent
system caused by
offsets.
D. Incorrect vent pipe.
E. Loose connections on
the vent safety wiring
harness.
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 or plug the hole.
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 air movement areas.
Checks vent pipe for blockage, such as bird nests, twigs, leaves, etc.
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.
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.
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.
Check the connection on both the switch and the gas valve. Tighten if
necessary.
CORRECTIVE ACTION