Hot water/combi boiler problem, no hot water

[Buzzc150]

Hi

I've been having an ongoing problem with our combo boiler. The hot water only works randomly. Most of the time there is no hot water. The heating seems to work ok. Occasionally a hot water demand from a tap will cause the rads to heat. We also get quite a violent banging from the pipework downstream of the boiler. Our local engineer diagnosed a faulty diverter valve which he has now been replaced with a new one but it has not cured the problem.
Any ideas ? Is it likely to be the electronics in the boiler sending faulty signals ?

Thanks

 

[Gasguru]

Make/model?

 

[Buzzc150]

RD 532

 

[Gasguru]

These boilers are around 15 years old but were a quality boiler.
Unless it has been very negelected it should have some life left.
I suggest you find a more competent engineer to take a look...there's little you can do yourself but given the fact that the fault is almost permanent should mean it's a straightforward repair.

 

[Buzzc150]

I've got some more info on my ongoing problem. Maybe someone can offer advice.
As mentioned before the new diverter valve did not help.
I believe the water is being overheated and the boiler is shutting off. The dial on the boiler shows the water being heated up to at least 99, even with the lowest selected value on the control knob. The boiler then shuts off. A few mins later there is loud banging noises and the hot water is released in to the radiators (is this a safety feature or a fault ?).
I installed a new towel rail a few years back and forget to put in inhibitor. Is the problem likely to be clogged or cracked heat exchanger ? It was suggested by a knowledgable friend that perhaps the expansion vessel is broken.
Any thoughts ?

 

[terryplumb]

Nothing to do with the EV. And nothing you can do yourself. You need an engineer.