Worcester Boiler - Fault has the engineer stumped (video)

[starblood]

Hello,

My mum has a Worcester Greenstar HE30 boiler (approx. 15 years old). Since its last service (and possibly coincidentally) it has been making a booming/banging sound randomly. This is a noise like a pocket of gas igniting and can be loud enough to make you jump. It's been impossible for the engineer to replicate when he visits, and as I say it can happen any time (though it is when you are drawing on the boiler, like when a hot tap is run for instance). Now the boiler is erroring out, and has become noisy - a whirring noise while operating.

The engineer has been back 4 or 5 times, done a few things* but the problem still continues. He's stumped, and thrown in the towel.

One last thing to mention - when the boom/bang happens, there is a strong smell of gas outside by the flue. I've actually managed to get a video of the fault in action - boom at 0.02 seconds and error at 0.40 seconds, whirring sound in between:

https://flic.kr/p/2nQXC5h

Any ideas/pointers I can give to the new engineer when he comes?

*ATTEMPTED FIXES
Visit #1: Loose wire
Visit #2: Replaced Gas Valve
Visit #3: Spark Electrodes fitted
Visit #4: Removed Butterfly Valve (didn't replace), reset, and replaced electrodes.

 

[CBW]

Put your trust in another engineer or use Worcester for a fixed price repair, sounds like a combustion issue.

 

[JonathanM]

This is a complete wild guess. But the bang sounds like the one I get on my freezer when the compressor turns off. But it's been like that since new. We sent the first one back, but the replacement was exactly the same. Expensive Swiss model, but the only one that fits in our gap.

 

[picasso]

At that age I would be checking the spark generator.

 

[starblood]

Cheers folks. I will pass on the observations people have made to the new guy who comes in to check the fault (and hopefully fix the problem).

I'll update the thread once the problem is sorted, so there is a reference for anyone with a similar issue.

 

[Alec_t]

IMO (I'm not a gas engineer) the whirring sound is the flue fan vibrating (worn bearing?). If the fan isn't shifting as much air as it should, could there be a build-up of gas in the flue, which then ignites when the spark is generated?

 

[starblood]

Just for completion, and to have this archived here if anyone encounters the same problem - turns out it was the PCB Board. They also replaced the butterfly valve.

British Gas Engineer fixed it, as all the local ones I tried were busy.

 

[ianmcd]

Just for completion, and to have this archived here if anyone encounters the same problem - turns out it was the PCB Board. They also replaced the butterfly valve.

British Gas Engineer fixed it, as all the local ones I tried were busy.

what is a butterfly valve ? do you mean the isolating valve ? why would they replace that ?

 

[starblood]

what is a butterfly valve ? do you mean the isolating valve ? why would they replace that ?

Sorry, not got much knowledge of boilers, hence the incorrect terminology. It was how it was described to me by the first Engineer. The proper name for the replaced part is a bearing plate.

Hope that makes more sense.

 

[ianmcd]

Sorry, not got much knowledge of boilers, hence the incorrect terminology. It was how it was described to me by the first Engineer. The proper name for the replaced part is a bearing plate.

Hope that makes more sense.

thank you that really made me smile , was wondering what you were referring to not much difference between a bearing plate and a butterfly valve