Worcester Boiler - Fault has the engineer stumped (video)

[starblood]

Hello,

My mum has a Worcester Greenstar HE30 boiler (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 starting to show an error status, 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:


Any ideas/pointers I can give to the new engineer when he comes? I have posted the question on another forum and there was a suggestion to check the spark generator. And another the flue fan.

*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.

 

[ShaunCorbs]

What’s the figures eg with his flue gas machine ?

 

[starblood]

Sorry folks. It doesn't look like the board will allow the embed of my Flickr video for some reason, coming up as a black box when I look? Worked on the other forum.

Can't even post a link to the Flikr page as it refuses saying it is spam.

EDIT: I've posted the video from Google Drive instead - hopefully everyone can see that in the original post

 

[starblood]

What’s the figures eg with his flue gas machine ?

I couldn't tell you I'm afraid. I wasn't there when he visited. My elderly mother was with him each time.

 

[Ricky]

Had the same with a new Vailiant, Valiant never came up with why, in the end gave customer a replacement boiler,
they said it may only go bang when certain types of NG is being used in the system.

 

[starblood]

Had the same with a new Vailiant, Valiant never came up with why, in the end gave customer a replacement boiler,
they said it may only go bang when certain types of NG is being used in the system.

That's very odd. This boiler was working fine until the service (I've got the video working now in the original post it you want to look)

 

[Gasmk1]

If he has changed electrodes, and not changed butterfly valve I would ask him too as the rubber goes hard and they don’t work correctly

 

[starblood]

If he has changed electrodes, and not changed butterfly valve I would ask him too as the rubber goes hard and they don’t work correctly

He's changed the electrodes twice, on two different visits. Not sure if he replaced the butterfly valve on the first change, but he completely removed it (without replacing) on the second change of electrodes (so the boiler now has no butterfly valve). He was completely stumped at this point to be fair and was trying different options. Said the butterfly valve wasn't that important, so it wasn't a problem leaving it out.

 

[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 fixed it, as all the local Engineers I tried were busy.