Sinclair error code F4

What it means

Outdoor coil temperature sensor fault.

Possible causes

Coil thermistor open or short Sensor mounting loose Harness insulation damaged

Suggested fix

Confirm sensor contact with the coil and check wiring integrity and resistance; repair mounting and harness and replace the thermistor if values are not within specification.

Safety first. Isolate the power supply before inspecting any unit. Refrigerant-circuit and electrical repairs must be carried out by a qualified, registered technician.
Other Sinclair codes
  • E1 — High pressure protection or system high-pressure fault.
  • E2 — System low-pressure fault.
  • E3 — System low-pressure protection (severe or repeated low-pressure event).
  • E5 — Current protection on compressor or fan circuit.
  • E6 — Communication error between indoor and outdoor units.
  • F1 — Indoor air (room) temperature sensor fault.
  • F2 — Indoor coil temperature sensor fault.
  • F3 — Outdoor ambient temperature sensor fault.
  • F5 — Discharge line temperature sensor fault.

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