Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 160 / 881

CHART 2104. TROUBLESHOOTING (AIR CONDITIONER)
Gauge Indication Probable Causes Remedy
High discharge pressure Overcharge of refrigerant Purge excess refrigerant
Air in system Check for leaks. Bleed charge
from system. Evacuate and
recharge system.
Overheated condenser due to Clean bugs and dirt from
blocking air passage. condenser fins. Straighten fins if
bent.
Flooded evaporator indicated Check that capillary bulb is
by heavy frosting on suction line securely clamped to suction line.
and compressor suction service If capillary bulb OK replace
valve. expansion valve.
Restriction in liquid line from Check for kinked hoses and
condenser. stopped up filter.
Low discharge pressure. Undercharge of refrigerant. Add refrigerant until bubbles
Sight glass shows bubbles or disappear. Check system leaks.
foam.
Damaged compressor valves or Replace compressor.
dirt under valves.
Damaged compressor. Worn or Replace compressor.
broken piston or piston rings.
Low suction pressure. Low air supply through Repair blower or blower motor.
(Accompanied by icing evaporator. Clean stoppage in air ducts.
evaporator.)
Very dirty evaporator fins and Clean and flush with water.
coils.
Low suction pressure.(Evaporator Undercharge of refrigerant. Add refrigerant. Install new
not cold enough) suction Moisture freezing in expansion dryer. Evacuate and recharge.
gauge may read a vacuum valve. Valve will show frost.
indicating evaporator lacks Expansion valve inlet screen
refrigerant. clogged. Inoperative expansion Remove screen. Clean with
valve. Valve stuck closed or solvent and replace. Warm
capillary bulb has lost its charge. capillary by holding in hand. If
suction pressure does not
change, replace expansion valve.
Restriction anywhere in liquid Locate restriction and repair.
line. Restriction will show frost.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
2 1 - 5 1 - 0 2
Page 21-49
Revised: May 15, 1989
1G16
PIPER AIRCRAFT