Piper Navajo Chieftain PA-31-350 Service Manual page 914

NAVAJO CHIEFTAIN SERVICE MANUAL
TABLE XIV-XV. TROUBLESHOOTING
CHART (AIR CONDITIONER) (cont)
Gauge Indication
Probable Causes
Remedy
Low suction
pressure.
(Accompanied
by icing evap-
orator.)
Low air supply
through evapora-
tor.
Repair blower or
blower motor.
Clean stoppage
in air ducts.
Very dirty evap-
orator fins and
coils.
Clean and flush
with water.
Low suction
pressure.
(evaporator
not cold
enough) suc-
tion gauge
may read a
vacuum in-
dicating evap-
orator lacks
refrigerant.
Undercharge of
refrigerant.
Moisture freezing
in expansion
valve. Valve will
show frost.
Expansion valve
inlet screen
clogged.
Inoperative ex-
pansion valve.
Valve stuck
closed or capillary
bulb has lost
its charge.
Add Freon.
Install new dryer.
Evacuate and re-
charge system.
Remove screen.
Clean with sol-
vent and replace.
Warm capillary by
holding in hand.
If suction pressure
does not charge.
replace expansion
valve.
Restriction any-
where in liquid
line. Restric-
tion will show
frost.
Locate restriction
and repair.
High suction
pressure.
Capillary bulb
clamp loose on
suction line.
Suction line
shows frost.
Clean contact
surfaces of suc-
tion line and
cap bulb.
Tighten clamp.
Expansion valve
not closing.
Evaporater flooded.
Suction line
frosted to com-
pressor.
Replace expansion
valve.
Reissued: 9/23/80
4H22
ACCESSORIES AND UTILITIES