Central Heating banging noise

[sotal]

We seem to be getting a bit of a banging noise from the central heating. I can't quite work out where from.

We had a new boiler fitted in May last year and hadn't really used the heating since.

It doesn't make the noise when the HW is on, on it's own.

It seems to make the noise most when the system is cooling down.

It's quite a loud crack sort of noise, it tends to just do it once at a time then might do it again 5 minutes later.

The boiler is located in the Garage so it's not coming from there. I can't quite pinpoint where the noise is coming from but it's in the house. It's just unpredicatable when it will make the noise.

It's a conventional boiler system, with a hot water cylinder in the airing cupboard. It's on a Y plan. The boiler is set to go to 88*C. The Boiler is an A rated Glow worm condensing boiler.

I've let air out of the radiators, there was just a bit in one (always tends to be the same one that gets any air in it)

Can't think of any other detail, other than to add the noise reminds us of the metal door knocker we had the last house just lifted and knocked once. (We haven't got a door knocker here before anyone asks!)

Any suggestions where to look?

 

[kevplumb]

Any suggestions where to look?

under the floor where the pipework was altered would be a good start

 

[sotal]

No pipework was altered, the boiler was fitted where the old one was. The noise sounds from the general area of the airing cupboard where the cylinder is but there are also two rads round there and obviously a lot of pipework under the floor round there which feeds to and from the airing cupboard

 

[slimlee]

have you got thermostatic heads (trv's) on the radiators?

 

[Servotech]

We seem to be getting a bit of a banging noise from the central heating. I can't quite work out where from.

We had a new boiler fitted in May last year and hadn't really used the heating since.

It doesn't make the noise when the HW is on, on it's own.

It seems to make the noise most when the system is cooling down.

It's quite a loud crack sort of noise, it tends to just do it once at a time then might do it again 5 minutes later.

The boiler is located in the Garage so it's not coming from there. I can't quite pinpoint where the noise is coming from but it's in the house. It's just unpredicatable when it will make the noise.



It's a conventional boiler system, with a hot water cylinder in the airing cupboard. It's on a Y plan. The boiler is set to go to 88*C. The Boiler is an A rated Glow worm condensing boiler.

I've let air out of the radiators, there was just a bit in one (always tends to be the same one that gets any air in it)

Can't think of any other detail, other than to add the noise reminds us of the metal door knocker we had the last house just lifted and knocked once. (We haven't got a door knocker here before anyone asks!)

Any suggestions where to look?

Im gonna be in big bother with the ARP lads by giving away a trade secret here; but if you introduce a mug ful of this stuff into your system the noise will be gone in an instant.
http://www.ciao.co.uk/Stergene_Delicate_Liquid_Wash__7624150
Schhh
I'll most likely get struck off from the Association Of Regulated Plumbers (ARP) now

 

[45yearsagasman]

The noise will be gone in an instant,doubtful, and a few months later so will your rads.Don't put that in.Noise might be related to 3 port valve? 88*C is probably a little high.

 

[slimlee]

It could be a trv fitted on the wrong side of one of the rads (return pipe). With the heating on and all the trv's open slowly turn down each trv one at a time and see if you can replicate the noise