COMPRESSORS
PROBLEM POSSIBLE CAUSE CHECK/CORRECTIVE ACTION
LOW COMPRESSOR
SUCTION PRESSURE
(and possible freezing of
the coil)
A) The room temperature is too low. See “ROOM TEMPERATURE TOO LOW”.
B) The air ow is too low or is absent. See “LOW AIR FLOW”.
C) The liquid line solenoid valve is not
completely open.
Check the valve opening.
D) The refrigerant lter is obstructed. Check the refrigerant lter.
E) The thermostatic valve is incorrectly
calibrated or defective.
Check the super heat setting of the thermostatic
valve; check that the sensor bulb has not lost
its charge and is well positioned, xed and
insulated.
F) There is an insufcient refrigerant charge.
Check the sub-cooling of the refrigerant liquid
at the condenser outlet;check to see if there are
any leaks and re-charge the unit.
PROBLEM POSSIBLE CAUSE CHECK/CORRECTIVE ACTION
THE COMPRESSOR
DOESN’T WORK
A) The short circuit protection has intervened.
Re-set the automatic switch and check the
cause of the short circuit.Before re-starting
the compressor, check the resistance and
continuity of the compressor motor windings.
B) The contactor is not working. Check the contacts and the contactor coil.
THE COMPRESSOR’S
INTERNAL
PROTECTION
INTERVENES
A) A phase is missing.
Check the resistance of the compressor motor
windings. After re-setting, measure the voltage
and current absorption of the three phases.
B) The motor is overloaded.
Check that the operating pressure of the unit is
within the predicted limits
C) The power supply voltage is too high or too
low.
Check that the voltage is within -10% and +10%
of the nominal value.
D) The rotor is blocked. Replace the compressor.
THE COMPRESSOR IS
NOISY
A) The compressor is damaged.
Call the nearest Service Centre in order to
replace the compressor.
B) There is liquid return to the compressor.
Check the setting and function of the
thermostatic valve.
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