Boiler making noises when switched off - any ideas?

dorsetlady

I have old boiler that's about 25 years old - it hasn't been serviced for a couple of years. Over the last couple of days it has been making loud noises when the water and heating are off. It starts by sounding like the boiler is starting up, and the gas is lighting, there is then a noise like water rushing and then some clunking noises. This lasts for about 30 seconds and repeats every 10-30 minutes. It did this one night in February but has been fine since. When the heating or hot water are on it's virtually silent.

Obviously, I'll have to get someone to look at it but any ideas what could be wrong with it?

tiggerbodhi

My combi does fire up when not being "used" as has a pre heat for the hot water, but this is a combi boiler is yours a combi?

keystone

dorsetlady wrote: »

I have old boiler that's about 25 years old - it hasn't been serviced for a couple of years. Over the last couple of days it has been making loud noises when the water and heating are off. It starts by sounding like the boiler is starting up, and the gas is lighting, there is then a noise like water rushing and then some clunking noises. This lasts for about 30 seconds and repeats every 10-30 minutes. It did this one night in February but has been fine since. When the heating or hot water are on it's virtually silent.

Obviously, I'll have to get someone to look at it but any ideas what could be wrong with it?

The sound of rushing water is probably air being pushed around by the circulator. The clunking noises if coming from the boiler imply that the boiler might have air in it too. When was the last time you bled the system? Have you tried doing it recently?

Secondly there is obviously a controls issue going on if the system tries to fire up from the "off" condition. That might or might not be associated with the physical manifestations you've described.

As always some more information about your system are needed. Boiler make/model, control system, open vented?, motorised valves? etc etc.

Cheers

dorsetlady

tiggerbodhi wrote: »

My combi does fire up when not being "used" as has a pre heat for the hot water, but this is a combi boiler is yours a combi?

No, it's not a combi.

dorsetlady

keystone wrote: »

The sound of rushing water is probably air being pushed around by the circulator. The clunking noises if coming from the boiler imply that the boiler might have air in it too. When was the last time you bled the system? Have you tried doing it recently?

Secondly there is obviously a controls issue going on if the system tries to fire up from the "off" condition. That might or might not be associated with the physical manifestations you've described.

As always some more information about your system are needed. Boiler make/model, control system, open vented?, motorised valves? etc etc.

Cheers

It's a Glow-worm Fuelsaver MKII. I've no idea about the other things you've asked. I've bleed the radiators but don't know what else may need bleeding. It's been fine all day today - it's just does it occassionally - I know it sounds silly but it really scares me - I hardly slept last night imagining the house might explode! :eek: