Error 138 - No heat pump control sensor

What does 138 mean?

The user interface displays '138: No heat pump control sensor', indicating that a critical sensor required for proper heat pump control is missing or not detected. This error typically triggers an automatic reset.

• Missing or disconnected control sensor.
• Faulty control sensor that is not sending a signal.
• Wiring damage to the control sensor preventing detection.

Click steps to track your progress.

1. 1

   Turn off the main power supply to the heat pump for 30 seconds, then turn it back on.

2. 2

   Check all control sensor connections, ensuring they are secure and correctly plugged in.

3. 3

   Allow time for the automatic reset to occur (default 6 hours) or use the manual reset function (Line 6711) if available.

4. 4

   Contact a qualified service technician to inspect or replace the heat pump control sensor.