Intermittent Hot water issue with Worcester Bosch Greenstar 35 CDI

[Pughheam]

I have a 16 year-old Worcester Bosch Greenstar 35 CDi combi boiler, which is recently suffering from intermittent issues with the hot water.

I usually get the shout from a family member who’s in the shower and found there’s no hot water. If I’m near the boiler when this happens, I can see the burner light is on, and then I can hear a banging sound coming from inside the boiler which last 3-5 seconds, before the burner cuts out and it all goes quiet, the temperature (2-char) display at this time is showing a number in the 80s or 90s.

I have discovered that if I power the boiler down and leave it for 15 mins, then most of the time it comes back on and operates normally. Other times it takes a few resets.

This issue happens about once ever 5or 6 weeks.

I have had it recently serviced, and during that time, the problem occurred for the engineer also.

He speculated that it might a faulty temperature sensor/regulator (or something like that) inside the boiler.

Any one got any ideas what it might me? Any advice would be really welcome.

Thanks,

 

[ShaunCorbs]

Do you have any other showers / problems with any taps ?

 

[Pughheam]

Do you have any other showers / problems with any taps ?

We have one other shower, but it is not usually on at the same time, and we do not have problems with any taps.

 

[Pughheam]

.. as I think about it, the banging sound could be described as a kind of ‘knocking’ sound

 

[ShaunCorbs]

Can you test that shower running as it could be the shower cartridge that’s gone

The banging is a overheating noise

 

[Pughheam]

Can you clarify what you mean by “… test shower running …”? The shower is running fine, and when the boiler is turned off and on again, the hot water is fine in all taps including the shower.

 

[ShaunCorbs]

I mean does the other shower make the boiler do the same fault ?