loud rattling from gas boiler

Our Vokera Maxin 24e has developed an occasional (well fairly regular in fact) loud rattling usually when it supplies hot water. It sometimes does is just on CH. It rattles for about 10 seconds and then the flame goes out, then it relights and repeats. The rattling is quite loud, as if someone is drumming on the metal case.

I guess this is a job for Vokera but I would not mind some advice on whyether to opt for the "£160 all in fix it" or the "parts and labour" deal.

any thoughts?

thanks,

Robert

Check the fan assembly.

Given the symptoms you describe I'd start with the fan. Very likely it has worn bearing and the fan is both touching its casing and ineffective.

Another thought might be a dodgy connection to the gas valve (I don't know how relevant that might be on that boiler). Might be able to tell if you can hear it after the fan starts but before it tries lighting the main burner.

THank you for your comments gentelmen. I think the fan is thge likely problem. NOw I think about it, the noise has been a bit off for a few weeks. Also, the way the flame goes out looks like a flame starved of air. We've turned it all off until the vokera man comes.

We bought the "fix all faults fincluding this one for a year " deal, for =A3300. Expensive, but it is an old boiler.

Robert

In case people are interested in what caused the rattling:

The guy from vokera came today and he found that the flue had come apart up in the loft! This meant it was discharging flue gases into the loft and also sucking the outlet gases back into the inlet in again causing the flame to stutter (loudly) and go out.

He was rather critical of the original installation for not supporting the flue sections, resulting in them gradually working loose and separating.

Quite a dangerous fault really... I'm annoyed I didn't think of checking up there before paying for Vokera to come and diagnose it for me. Ah well.

Robert

What length of flue is in the loft? Anything where the flue is over one metre needs to be braced (supported). How old is the system? And, is the original installer coming back to get his wrists slapped for nearly killing you and your family?

Glad you've got that one sorted.

There's about 2 metres of unsupported flue pipe going vertically up through the loft and with a 1 metre dog leg. it's been like that for

I assumed it was designed to stand alone like that!

Robert

There's about 2 metres of unsupported flue pipe going vertically up through the loft and with a 1 metre dog leg. it's been like that for

I assumed it was designed to stand alone like that!

Robert

Where the dog leg comes off, is there any support rods taking the weight at the bends? They should be taken from close to the bends as possible, up to the roof timber to take some of the stress off the angle connectors. Two rods, at least, one at each end of the short dog leg section.

Will this problem happen again? Maybe in a shorter period of time because the pipes have now been loosened off.

It's amazing how much vibration goes up the flue pipe.

I would say that was money *well* spent.

Was it done by a corgi?

CORGI would be very interested to slap the installers wrists or more.