Tristar Compressor Discharge Temperature Protection

Unit displays F4 and does not start compressor; fan may still run.

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

Blocked outdoor coil or airflow, Low refrigerant charge causing overheating, Faulty discharge temperature sensor, Non-condensable gases in system

Safety first: Turn off power. Do not touch hot refrigerant lines immediately after shutdown.

User-level steps:

Clean outdoor coil: Remove debris and wash fins gently.
Check outdoor fan: Ensure the fan runs at full speed when the unit is on.
Shade and ventilation: Ensure the outdoor unit is not enclosed or exposed to extreme direct heat without airflow.

Technician-required: A professional should verify discharge sensor operation, refrigerant charge, and system pressures.

Hard 4/5

Discharge Temperature Sensor

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