Ipm Power Module Protection - Haier H-MRV Series Service Manual

5. IPM power module protection

9 flashes of outdoor ALARM light.
Possible causes: 1. Short-circuit or overcurrent
1.Four-way control supply (15VDC) is less than 13.5V.
2.Module is hot with a temperature higher than 145° C.
Are CN1 and CN2 in
mainboard in poor contact?
no
Is 10-pin connector between IPM
and mainboard short-circuit or in
poor contact?
no
Is output voltage of rectifier
acceptable (310VDC at 220V. Less
than 250V when running at high
frequency.)
yes
Check point: CN2 in mainboard.
Is four-way supply voltage less than
13.5V (normal value: 13.5-16.5VDC)
no
Is compressor in good condition?
yes
Is power module too hot?
no
Is current up to
protection limit of
power module?
no
1.Is output voltage among U, V and W balanced?
2.Disconnect all terminals. Is resistance between P
and N; P and U, V, W; N and U, V, W acceptable?
yes
Check mainboard and make
necessary replacement
yes
Check and reconnect
yes
Replace cable
no
Replace rectifier
yes
Replace PCB
no
Is compressor winding resistance
acceptable? Is it blocked?
yes
Is silica gel well distributed on radiation fins?
1.Is voltage of supply circuit too low?
yes
2.Is heat exchanger or indoor fan motor broken?
3.Is ambient temperature too high? Is system
overloaded?
no
Replace power module
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