Outdoor Heat Exchanger Sensor (ThOR) Defective or High Pressure

What does E35 mean?

The outdoor unit's heat exchanger sensor (ThOR) is defective (open or short circuit) or has a poor connection to the outdoor unit PCB. This can also indicate excessively high cooling pressure, compromising system efficiency and safety.

1. 1

   Measure the resistance of the ThOR sensor at its leads — compare to a resistance-temperature chart if available.

2. 2

   Inspect the ThOR sensor's connector on the outdoor unit PCB — verify it is securely seated.

3. 3

   Measure system high-side pressure using manifold gauges during cooling operation.

4. 4

   Verify condenser coil cleanliness and airflow if high pressure is observed.