F75 Fault — Pump/water shortage or sensor/pump defective

What does F75 mean?

This fault indicates issues with the pump, a water shortage, or a defective water pressure sensor. It can also be caused by air in the heating system or blockages.

• Water pressure sensor and/or pump defective
• Air in the heating installation
• Insufficient water in the system
• Blocked rubber connection hoses on flow and return
• Blockage in boiler somewhere

Click steps to track your progress.

1. 1

   Check the boiler's water pressure and add water if necessary to reach the correct operating range.

2. 2

   Check if the pump is spinning correctly; if not, check the voltage to the pump from the PCB (requires specialist tools).

3. 3

   Ensure the pressure sensor is not blocked.

4. 4

   If present, check rubber connection hoses on flow and return pipes for blockages.

5. 5

   Bleed the heating system to remove any air.