Worcester 240 Combi BF - Bang, Gurgle,Pilot Out, Not working

[MoiraP]

Hi,
My Worcester Combi 240bf has expired. When I turn on the hot water there is a loud bang and series of gurgling noises from the boiler then it cuts out and the pilot goes out. I can light it after a short while.

The problem doesn't happen when i use it for central heating only.

Any thoughts.

 

[chrishutt]

Yes...first, stop using the boiler..... second, get competent Corgi reg. engineer to look at it. Sounds serious, so I wouldn't suggest trying anything yourself unless you happen to have good working knowledge of combis....

 

[kevplumb]

glasgow
ask DP
he is in your neck of the woods

 

[MoiraP]

Thanks,
I'll look DP up, can't find anyone in Greenock who'll answer the phone.
I've been told it may be worthwhile replacing the boiler as its 10 years old. Is this valid or should I get it reaired

 

[chrishutt]

10 years isn't all that old for a boiler. Worcester's have good reputation and could be expected to soldier on for maybe 20 years if looked after. However it may have suffered some damage from the fault you describe. Only an experienced engineer can make that sort of judgement.

But bear in mind that a new boiler would probably have to be a condensing combi - more expensive to buy and fit (£1,500+ ?), possibly with flueing complications, although cheaper to run (at least until it goes wrong).

 

[ChrisR]

I for one would be interested to hear what caused the problem. I can only think of obscure things!

 

[MoiraP]

Had a gas board engineer in today. He found that the pump was faulty and relaced it. Problem fixed.

 

[chrishutt]

Moira wrote

When I turn on the hot water there is a loud bang

Can't quite see why a faulty pump should cause above symptoms. Anyone have a theory?

 

[ChrisR]

That's the way I was thinking, hence the puzzlement. The AAV coul have been shut holding air in the boiler, but then it would have complained on CH as well.
How LONG after turning the HW on did it first bang?

 

[alrogers]

The boiler is overheating (probably) Without seeing it and testing its hard to diagnose but generally a pump down prvents the water circulating through the heat exchangers and causes the overheat or high limit stat to cut and shut the boiler down completely. If I remember correctly the 240 has an automatic reset on the stat. thats why you can turn it on - after its cooled down.

First post, hello all

 

[chrishutt]

Hi alrogers, welcome to the forum.

I think you're right about what would have happened, but we were wondering about the "loud bang" that the poster reported. Would you expect that with an overheat? I would have thought a series of not so loud bangs would have been more typical.

 

[ChrisR]

Welcome Al. How would it be OK on CH then!? Would overheat about as quickly with no pump. There's more to this!

 

[chrishutt]

ChrisR, I thought about that too, but remembered that quite often the gas rate is set much lower on central heating, so the same symptoms might not manifest themselves, at least not in the short time the CH might be run to "test it".