Main Protection - Midea MS9A-05CR-QD0 Service Manual

8.3 Main Protection

8.3.1 Time Delay at restart for compressor.
8.3.2 Fan Speed is out of control.(except MS9A-21HR-QB6W and MA9A-24HR-QB4W models)
----When Indoor Fan Speed keeps too low or too high for certain time, the unit will stop and the LED
will display the failure
8.3.3 Current protection
A
I3SEC
B
I5MIN
C
IFAN
IRESTORE
Resume
A zone : The current exceeds I for 5 seconds, the compressor and outdoor fan will shut off.
3SEC
B zone: The current exceeds I for 5 minutes, the compressor and outdoor fan will shut off.
5min
C zone: The current exceeds I , the outdoor fan will shut off if AC is in heating mode. If AC is in
FAN
cooling mode, the indoor fan will run at low speed.
8.3.4 Zero crossing detection error protection(except MS9A-21HR-QB6W and
MA9A-24HR-QB4W models)
If AC can not detect zero crossing signal for 4 minutes or the zero crossing signal time interval is not
correct, the unit will stop and the LED will display the failure. The correct zero crossing signal time
interval should be between 6-13ms.
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