Outdoor Heat Exchanger Thermistor 2 Failure (Tho-R2)

What does E37-2 mean?

The second outdoor heat exchanger thermistor (Tho-R2) is defective. This prevents accurate temperature measurement of a specific section of the outdoor coil, impacting system control and protection.

1. 1

   Measure the resistance of thermistor Tho-R2 at its leads — compare to a resistance-temperature chart if available.

2. 2

   Inspect the connector for Tho-R2 on the outdoor unit PCB — verify it is securely seated and free from corrosion.