Viessmann Inverter Module Temperature Sensor Fault

System stops; P4 error; may be associated with abnormal compressor behavior

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Defective IPM temperature sensor, Poor thermal contact between sensor and heat sink, Faulty inverter PCB, Sensor wiring damage

Safety: Only qualified technicians should work on inverter modules.

Visual inspection: With power off, inspect the inverter heat sink and sensor mounting.
Check sensor connection: Ensure the sensor plug is firmly seated on the PCB.
Replace inverter board: On many designs, the sensor is integrated into the inverter module; replacement of the entire board is required if faulty.

Professional Required 5/5

Outdoor Inverter Control Board

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