Sinclair SCV-750EB Service Manual page 92

5.12 P4, P5 Troubleshooting
Digital display output
Description
1 P4 indicates system A current protection
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2 P4 indicates system A DC bus current protection
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1 P5 indicates system B current protection
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2 P5 indicates system B DC bus current protection
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When the compressor current rises above the protection value 33A, the system displays P4 or P5 protection and all units
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stop running. When the current returns to the normal range, P4 or P5 is removed and normal operation resumes. When P4
or P5 error occurs 3 times in 60 minutes, a manual system restart is required before the system can resume operation.
Error code is displayed on main PCB and user interface.
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Possible causes
Power supply abnormal.
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Poor condenser heat exchange.
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High pressure side blockage.
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Excess refrigerant.
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System contains air or nitrogen.
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Inverter module damaged.
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Compressor damaged.
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Main PCB damaged.
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