Isuzu 2000 Trooper Workshop Manual page 71

1A–42 HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Condition
Discharge (High Gauge) Pressure
Abnormally Low.
Frost or dew on refrigerant line
before and after the receiver/drier or
expansion valve, and low pressure
gauge indicates vacuum.
Discharge (High Gauge) Pressure
Abnormally Low.
High and low pressure gauge
balanced quickly. (After turned off
A/C)
Suction (Low Gauge) Pressure
Abnormally High.
Low pressure gauge (Low pressure
gauge is lowered after condenser is
cooled by water.)
Suction (Low Gauge) Pressure
Abnormally High.
Low pressure hose temperature.
(Low pressure hose temperature
around the compressor refrigerant
around the com ressor refrigerant
line connector is lower than around
evaporator.)
Suction (Low Gauge) Pressure
Abnormally High.
High and low pressure gauge
balanced quickly. (After turned off
A/C)
Suction (Low Gauge) Pressure
Abnormally Low.
Insufficient cooling.
Suction (Low Gauge) Pressure
Abnormally Low.
Frost on the expansion valve inlet
line
Suction (Low Gauge) Pressure
Abnormally Low
Receiver/drier inlet and
refrigerant line temperature.
distinct difference in temperature
develops.)
Suction (Low Gauge) Pressure
Abnormally Low.
Expansion valve outlet refrigerant
line. (Not cold and low pressure
gauge indicates vacuum.)
Suction (Low Gauge) Pressure
Abnormally Low.
When the refrigerant line is clogged
or blocked, the low pressure gauge
reading will decrease, or a vacuum
reading may be shown.
Suction (Low Gauge) Pressure
Abnormally Low.
Evaporator core is frozen.
Possible cause
Restriction caused by debris or
moisture in the receiver/drier.
Compressor seal defective
Poor compression due to a defective
compressor gasket.
Excessive refrigerant in system.
Unsatisfactory valve operation due
to defective temperature sensor of
expansion valve.
Expansion valve opens too long.
Compressor gasket is defective.
Insufficient refrigerant in system.
Expansion valve clogged.
Receiver/Drier clogged.
outlet
(A
Expansion valve temperature sensor
is defective.
Clogged or blocked refrigerant line.
Thermo switch defective.
Correction
Check system for restriction and
replace the receiver/drier.
Repair or replace the compressor.
Repair or replace the compressor.
Discharge and recover refrigerant
Recharge to specified amount.
Replace the expansion valve.
Replace the expansion valve.
Repair or replace the compressor.
Check for leaks. Discharge and
recover the refrigerant. Recharge to
specified amount.
Replace the expansion valve.
Replace the receiver/drier.
Replace the expansion valve.
Replace refrigerant line.
Replace thermo switch.