Puma 80e odd fault

[RPFeynman]

I replaced the diverter due to no, of little, CH

Now I have a nice silent boiler in CH mode and rads are hot.

But turn on the hot taps and the boiler gets very noisy and then trips!

The only thing I can think of is the new valve has failed...any other ideas?

 

[mickyg]

heat exchanger scaled up

 

[RPFeynman]

heat exchanger scaled up

Would you recommend de-scaling it or replacement?

 

[bengasman]

If the boiler trips repeatedly, it is probably time to get it checked by an RGI.

 

[baxpoti]

Hot water switch coould be sticking on, very common problem.

Check the red led goes out when the tap turns off.

 

[RPFeynman]

Hot water switch could be sticking on

It isn't that because it trip while hot taps are on full.

Also, if I turn the Hot Water control on the boiler to minimum the tripping stops.

What I suspect is happening is the water within the CH part of the Heat Exchanger is over heating thus tripping the CH overheat stat. The question is why is the CH part overheating.

When I installed the boiler I made sure I included a bypass circuit that pushes the water though a bathroom towel rail which is still working (not blocked)...

Does anyone know how the boiler is supposed to keep the CH part cool while supplying DHW?

 

[mickyg]

heat exchanger scaled up

Would you recommend de-scaling it or replacement?

personally I would recommend replacing the boiler. But yes, you could have the heat exchanger removed and de-scaled if that is the problem(could be problematic and cost a few quid). However I was only offering one possibility, as it is a common problem my way because of the ridiculously hard water.