37MGRA PC 03 Pressure Protection (low or high pressure), PC 30 High Pressure Protection, PC 31 Low Pressure Protection (Diagnosis and Solution)

37MGRA Diagnostic Codes

Diagnostic codes covered

PC 03(PC03), PC 30(PC30), PC 31(PC31)

  • PC 03 – Low- or High-Pressure Protection

Description: Outdoor pressure switch cut off the system because high pressure is higher than 638 psi or outdoor pressure switch cut off the system because low pressure is lower than 19 psi, the LED displays the failure code. Recommended parts to prepare: Connection wires, Pressure switch, Outdoor fan, Outdoor main PCB, Refrigerant Troubleshooting and repair:

Troubleshooting workflow

PC 03 Pressure Protection (low or high pressure), PC 30 High Pressure Protection, PC 31 Low Pressure Protection (Diagnosis and Solution) workflow
PC 03 Pressure Protection (low or high pressure), PC 30 High Pressure Protection, PC 31 Low Pressure Protection (Diagnosis and Solution) workflow
PC 03 Pressure Protection (low or high pressure), PC 30 High Pressure Protection, PC 31 Low Pressure Protection (Diagnosis and Solution) workflow
PC 03 Pressure Protection (low or high pressure), PC 30 High Pressure Protection, PC 31 Low Pressure Protection (Diagnosis and Solution) workflow

Workflow source: original 37MGRA-02SM service-manual PDF. Error-code names cross-checked against 37MGRA-04SI.

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