Troubleshooting - Midea LSBLG MCF Series Technical & Service Manual

Flooded type water cooled screw chiller (MIC)

2. Troubleshooting

No. Alarm Trouble Description
Power Failure Phase sequence relay
1
Protection switches OFF
Compressor Motor Compressor motor module
2
Protection switches OFF
Excessive current and
Compressor Overload
3 cumulated energy cause the
Protection
thermal relay to trip
The coil of the contactor
4 Contactor Protection does not perform suction
normally
5 Anti-freezing Protection Anti-freezing switch OFF
The water flow switch
6 Water Flow Fault disconnects for more than
5s
Action Reset Type
Compressor cannot work. The
Reset it manually on the touch
compressor stop running
screen
immediately
Power off the unit and
Compressor cannot work. The
re-power up the electricity,
compressor stop running
reset manually on the touch
immediately
screen
The compressor will stop Reset it manually on the touch
running immediately screen
The compressor will stop Reset manually on the touch
running immediately screen
The compressor will stop Reset it manually on the touch
running immediately screen
1.The compressor cannot work.
The compressor stops running
immediately ；
2. Chilled water flow failure: The
chilled water pump stops
Power off the unit and
working after 30s delay; Cooling
re-power up the electricity,
water pump and cooling tower
reset manually on the touch
shut down after 120s delay
screen
3.Cooling water flow failure: The
cooling water pump and cooling
tower shut down after 30s delay;
chilled water pump stops
working after 180s delay.
102
MCAC-CTSM-2018-1
Possible Cause
The power quality is poor due to phase inversion,
lacking phase or phase imbalance.
1 The power of motor is poor due to phase
inversion, lacking phase, over-voltage,
under-voltage
2. The motor overheats
1,The compressor continues running in bad
conditions like over-current.
2,The setting value of thermal relay is too low
1.The suction of the contactor is abnormal when
Y type switches to △ type
2.The vibration during operations cause the
contact to loosen
1,The chilled water flow falls sharply, the water
temperature too low
2,Anti-freezing switch is damaged or wiring
connection is abnormal
1,The water pump fails and the water flow is too
small
2,Water flow switch fails or the wiring connection
is incorrect