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HVAC
36
REFRIGERATION CYCLE TROUBLESHOOTING
Sr.
No.
OCCURANCE
POSSIBLE CAUSE
REMEDY
5
Expansion valve malfunc-
tioning (opening too
much) and improper in-
stallation
of
heat
sensitizing tube.
Condition
Air conditioner does not cool effective-
ly.
Symptoms in refrigerant cycle
Pressure on both the low and high.
pressure sides is high.
Frost or heavy dew is formed on the
piping on the low pressure side.
Cause
The expansion valve is malfunctioning
or the heat sensitizing tube is improp-
erly insstalled.
Flow control is not properly performed
Diagnosis
Excessive liquid refrigerant in the low
pressure side piping.
Expansion valve opened too far.
Countermeasures
Check the installation of the
heat sensitizing tube.
If the installation is proper,
replace the expansion
valve.
6
Faulty compression of
compressor
Condition
Air conditioner does not cool. Symp-
toms in refrigerant cycle
Pressure on the low pressure sides is
too high and pressure on the high
pressure side is too low.
Cause
There is leaking in the compressor
Diagnosis
Faulty compression of compressor.
Delivery valve or packing is leaking or
broken or compressor is malfunction-
ing.
Countermeasures
Check the compressor oil
for contamination and quan-
tity.
Replace the compressor.