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Vol. 2.6 © 2020 Hanbell Precise Machinery Co., Ltd. All rights reserved
6.6 Troubleshooting
The table below shows some problems that might occur at the jobsite. This table will
only be served as a guide for engineers to understand the situation once the problem
occurs.
Problem
Possible cause
Action
Sudden trip
of the motor
thermostat
/sensor
Refrigerant shortage
Charge refrigerant
Unstable electricity system or power failure
Check power supply
Motor overloaded
Check motor condition.
Bad motor coil causing temperature rising
rapidly.
Check the coil or the motor stator.
Poor insulation
of the motor
Bad motor coil.
Check the coil or the motor stator.
Motor power terminal or bolts are wet or frosty.
Check power bolt.
Motor power terminal or bolts are bad or dusty.
Check power bolt.
Acidified internal refrigeration system.
Clean the system.
Motor coil running long time continuously
under high temperature.
Check liquid injection condition.
Compressor
starting failure or
Y-
Δ
shifting
failure
Voltage incorrect.
Check power supply
Motor failure
Replace the motor
Incorrect power supply connection.
Check and reconnect it
Y-
Δ
timer failure.
Check or replace it
Rotor jam
Check and repair it
Protection device trip
Check devices
Abnormal
vibration and
noise of the
compressor
Damaged bearings.
Replace bearings.
Insufficient lubricant.
Check oil level of the compressor if
enough, or add some oil if necessary.
Working out of the operating limit (surge)
Check the operating range.
Improper pipe system.
Check the system piping.
Unbalanced motor rotor
Check and balance the rotor.
High
discharge
temperature
Insufficient refrigerant.
Check leakage. Charge additional
refrigerant and adjust suction superheat
less than 1
℃
Condenser problem due to low efficiency.
Check and clean the condenser.
Refrigerant is overcharge.
Reduce refrigerant
Air/moisture in the refrigerant system
Recover and purify refrigerant and
vacuum system.
Improper expansion valve using
Replace and adjust proper suction
super-
heat
Oil loss
Improper system piping
Check the oil pump
Low suction
pressure
Lack of refrigerant
Check leakage. Charge additional
refrigerant.
malfunction of the expansion valve
Check and reset for proper superheat
Note: