F.71 — Flow NTC fault

What does F.71 mean?

The flow temperature sensor is signaling a constant or unchanging value, indicating it is either faulty or incorrectly positioned and unable to detect temperature changes.

• Flow temperature sensor is incorrectly positioned at the supply pipe.
• Flow temperature sensor is defective.

Click steps to track your progress.

1. 1

   Press the fault clearance key on the boiler to reset it.

2. 2

   If accessible, visually check the positioning of the flow temperature sensor.

3. 3

   If the fault persists, contact Vaillant Service Solutions to inspect or replace the sensor.