37MGRA PH 90 (High temperature protection of evaporator diagnosis and solution)

Diagnostic codes covered

PH 90

Description: When evaporator coil temperature is more than 60°C in heating mode, the unit stops. It starts again only when the evaporator coil temperature is less than 52°C. Recommended parts to prepare: Connection wires, Evaporator coil temperature sensor (T2), Indoor fan, Indoor main PCB

Troubleshooting workflow

PH 90 (High temperature protection of evaporator diagnosis and solution) workflow
PH90 (High temperature protection of evaporator diagnosis and solution) workflow

Related diagnostic checks

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

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