F64 Fault — Flow or return temperature sensor short circuit or electronics fault

What does F64 mean?

The flow or return NTC temperature sensor has a short circuit, or there's a general electronics issue.

• Flow or return NTC short circuited
• Electronics defective
• Wiring harness continuity issue

Click steps to track your progress.

1. 1

   Check the resistance on the thermistors (temperature sensors) (requires specialist tools).

2. 2

   Check the continuity down the wiring harness connected to the sensors (requires specialist tools).

3. 3

   If both resistance and continuity are fine, the PCB may be faulty (contact a technician).