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HVAC
44
REFRIGERATION CYCLE TROUBLESHOOTING
Sr.
No.
Possible Cause
Remedy
5
Expansion valve mal-
functioning (opening
too much) and im-
proper installation of
heat sensitizing tube.
Condition
x
Air conditioner does not cool effective-
ly.
Symptoms in refrigerant cycle
x
Pressure on both the low and high.
pressure sides is high.
x
Frost or heavy dew is formed on the
piping on the low pressure side.
Cause
x
The expansion valve is malfunctioning
or the heat sensitizing tube is improp-
erly installed.
x
Flow control is not properly performed
Diagnosis
x
Excessive liquid refrigerant in the low
pressure side piping.
x
Expansion valve opened too far.
Countermeasures
x
Check the installation of
the heat sensitizing tube.
x
If the installation is proper,
replace the expansion
valve.
6
Faulty compression of
compressor
Condition
x
Air conditioner does not cool.
Symptoms in refrigerant cycle
x
Pressure on the low pressure sides is
too high and pressure on the high
pressure side is too low.
Cause
x
There is leakage in the compressor
Diagnosis
x
Faulty compression of compressor.
x
Delivery valve or packing is leaking or
broken or compressor is malfunction-
ing.
Countermeasures
x
Check the compressor oil
for contamination and
quantity.
x
Replace the compressor.