Piper Navajo PA-31 Service Manual page 969

PIPER NAVAJO SERVICE MANUAL
TABLE XIII-I. TROUBLESHOOTING CHART (HEATING SYSTEM) (cont.)
Trouble
Cause
Remedy
Heater fails to light.
(cont.)
Ignition vibrator inop-
erative.
Replace vibrator. Check
for defective ignition
unit. (Refer to Paragraph
13-30.)
Manual reset limit
(overheat) switch open.
Press reset button firmly
and recheck to determine
reason for switch open-
ing.
Combustion air pressure
switch open. (Defective
switch or low combus-
tion air blower out-
put.)
Check for low blower out-
put due to low voltage and
correct it. If switch is
defective, replace it.
(Refer to Paragraph 13-36.)
Cycling switch open.
Duct switch open.
Replace if defective.
(Refer to Paragraph 13-34.)
Operate control to see if
switch will come on. Re-
place switch if defective.
(Refer to Paragraph 13-38.)
Ventilating air blower
fails to run.
Heater switch "OFF."
Broken or loose wiring
to motor.
Energize the heater
switch. Check and repair
wiring.
Circuit breaker open.
Worn motor brushes.
Blower wheel jammed.
Close circuit breaker.
Replace motor brushes.
(Refer to Paragraph 13-26.)
Remove and check the
ventilating air blower
wheel and realign if
necessary. (Refer to
Paragraph 13-47.)
HEATING AND VENTILATING SYSTEM
Reissued: 10/12/79
5D15