F75 fault but different

[davidjg]

My Vaillant ecotec pro 24 boiler has a recurring f75 fault but only when the central heating is turned on. When its set to HW only its fine. Pressure is showing at about 2 bar rising to 2.3 when pump engages. The boiler is only about 3 yrs old and was serviced about 9 months ago. Ive read about the infamous F75 but cant find anything where it only happens when CH is switched on. Any ideas please ?

 

[muggles]

There will be less of a pressure change when the CH comes on to when the boiler is producing DHW so I'd expect it to fault on CH first. Get someone out with a good knowledge of Vaillants and F75 causes and they should be able to diagnose and fix for you. Nothing to DIY on these I'm afraid as the white front cover forms the room seal and should therefore only be removed by a Gas Safe Registered Engineer

 

[Agile]

There is something that needs to be done when the boiler is serviced which has a significant effect on preventing the F75 fault.

Unfortunately few actually do that on a service.

In fact many only check the composition of the flue gases and don't even open up the boiler!

Tony

 

[Agile]

There is something that needs to be done when the boiler is serviced which has a significant effect on preventing the F75 fault.

Unfortunately few actually do that on a service.

In fact many only check the composition of the flue gases and don't even open up the boiler!

Tony

 

[hertsboilers]

Good luck for OP, as hell of lot gas engineers thinking to replace pump for F75 problem.

Get a good engineer!

 

[Bunnyman]

In Kent try mark here
http://vaillantservice.co.uk/VAILLANT/Vailliant_Home_Boiler_Repairs_Servicing_Faults.html