Troubleshooting ... (cont.)
SYMPTOM
4, Furnace operates but turns "Off" before room
temperature is attained.
5.Furnace not producing sufficient heat.
6.Furnace operates but will not shut "Off" when room
temperature is attained.
7.Pilot outage problem.
8.Abnormal operation.
POSSIBLE CAUSE
A, Sensing bulb not located properly. (Bulb control model,)
B. Temperature dial out of
calibration. (Bulb control model.)
C. Thermostat location. (Wall thermostat model.)
D.Defective thermostat. (Wall thermostat model.)
A.Furnace may be too small for space being heated.
B.Furnace not burning at full rate.
A. Sensing bulb not located properly. (Bulb control model.)
B. Temperature dial out of calibration. (Bulb control model.)
C. Bulb or capillary broken. (Bulb control model.)
D. Thermostat wiring defec- tive. (Wall thermostat model.)
E. Thermostat location. (Wall thermostat model.)
EDefective thermostat. (Wall thermostat model.)
G.Dirt under valve seat or valve stuck open.
A.Pilot flame may be low or blowing (high) caus- ing safety to drop out.
A.Delayed ignition - pilot flame may be too low.
B.Expansion noise ticking.
CORRECTIVE ACTION
Check location of sensing bulb - should be attach- ed to back of control valve.
See valve manufacturer's instructions.
Check thermostat location - should not be in the path of warm air discharge from furnace, near a lamp, or above a "IIV. or stereo set.
Check thermostat calibration or replace.
Check heat loss calculations.
Check for low gas pressure (see 3B page 21). Check burner orifice.
Check location of sensing bulb - should be attach- ed to back of control valve.
See valve manufacturer's instruction.
Replace valve.
Thermostat lead wires may be shorted together caused by a nail or staple - check by removing ther- mostat leads from valve terminals.
Check thermostat location - if on an outside wall
or a hole in wall behind thermostat is causing cold air to contact thermostat - relocate.
Check thermostat calibration or replace.
Replace valve.
Adjust pilot flame. Check vent tube and air inlet tube (see 3A page 21). Be sure pilot lighting door is clos- ed. Pilot orifice or aerating hole may be plugged (check for spiders, webs or other organic material).
Adjust pilot flame.
Check installation - casing may be distorted by be- ing fastened to an uneven wall. Vent tube and air inlet tube may be in a bind with vent cap assembly
-be sure hole through wall is correct and parts fit without binding.
