Piper Navajo PA-31 Service Manual page 968

PIPER NAVAJO SERVICE MANUAL
TABLE XIII-I. TROUBLESHOOTING CHART (HEATING SYSTEM)
Trouble Cause
Remedy
Heater fails to light.
Heater switch or circuit
breaker open.
Turn on heater switch or
close circuit breaker.
Low voltage supply.
Regulator not operating
properly.
Apply external power
supply. Attempt to start
heater. (Refer to Para-
graph 13-14.)
Check for low pressure.
If it is not regulating
at 7.5 ± 0.5 psi, ad-
just regulator to that
value or replace regu-
lator. (Refer to Para-
graph 13-37.) (See Note.)
NOTE
When making the fuel pressure check, be sure fuel is flowing
through the nozzle. Turn the adjusting screw clockwise to increase
fuel pressure and counterclockwise to decrease it.
Restriction in fuel noz-
zle orifice.
Fuel heater solenoid
not operating.
Fuel lines clogged or
broken.
Remove the nozzle and
clean or replace it.
(Refer to Paragraphs
13-40, 13-44 and 13-47.)
Remove and check sole-
noid. Replace if faulty.
(Refer to Paragraphs
1340, 13-44 and 13-47.)
Inspect all lines and con-
nections. It may be nec-
essary to disconnect
lines at various points
to determine where the
restriction is located.
Reissued: 10/12/79
HEATING AND VENTILATING SYSTEM
5D14