Sinclair SCV-50EA Service Manual page 79

P1 malfunction: High pressure protection
Judge whether the wiring connection is correct.
Judge wire body is broken or not.
To confirm: short-circuit high pressure switch and check whether
the system can operate normally or not.
Check whether the cooling system is normal or not.
Check whether pressure of the system is too high.
Whether side air duct of outdoor unit meets the standard.
Whether the heat exchanger needs cleaning.
Whether the pipeline is blocked.
Judge the circulation water pump is damaged or not.
Whether plate heat exchanger is fouling or blocked severely
LED displays P1
High pressure protection
YES
YES
NO
YES
NO
NO
NO
NO
Replace main PCB.
NO
NO
Replace high pressure switch.
YES
NO
YES
Clean.
YES
Rectify the pipeline.
YES
Repair or replace the water pump
YES
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Connect again.
Stop the system.
Rectify the air duct
Clean or replace heat exchanger .