The Vaillant Ecotec F75 fault code is one of the most common for this boiler.
So what is the F75 fault?
The f75 fault code indicates that the pressure sensor inside the boiler hasn’t picked up a difference in pressure when the pump has kicked in.
The pressure sensor needs to pick up a 0.2bar increase when the pump runs.
A lot of engineers will go straight to changing the pump or the sensors, but this isn’t always the case.
The sensor not picking up a pressure difference can be down to a number of different things, such as:
- Faulty pump
- Blocked pump
- Faulty sensor
- Blocked sensor
- Lack of water in system
- Blocked flow and return pipework (internal)
- Failed expansion vessel
- PCB fault (very rare, but can be a cause)
- Blocked main heat exchanger
All the points above can be a reason for your boiler showing the F75 fault code.
You can check the water pressure in the boiler but the gauge in the bottom right hand corner, or you can press the “–” button on the display.
Unfortunately not the easiest fault to repair, and if you get the wrong engineer to do it, not the cheapest!
We hope that this has helped you, and for more information please feel free to contact us and we will do all we can to help!
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