Is it pipe expansion or not?

[noisypipes]

I've had a new Baxi boiler fitted in Oct. The old boiler was upstairs and the new is downstairs in the garage.I never had any noise from the old system but now I'm getting noises in the bedrooms and bathroom upstairs which the plumber says is pipe expansion.They've just re-done the power flush (which was poorly done 1st time and gas was building up in the bathroom rad) and replaced the TRVs on the upstairs rads but the noise persists.the noise happens each time the boiler kicks in but what I can't understand is that it becomes worse (louder and more frequent) when the heating has been on for several hours. Why should this be if it was pipe expansion? They do not want to take up all my floorboards looking for a problem pipe(understandably) but I am left with a heating system that I cannot have on because it is too noisy. Please can anyone suggest any other possible causes?? I am at my wits end.

 

[John506]

What kind of noise is it? Is it a clicky noise?

 

[noisypipes]

Well, not a quiet click - more of a rapid "donk donk donk" kind of noise which continues for a minute and then stops. then the whole thing starts again 4 minutes or so later. If it IS expansion, why does it get worse when the heating's been on for a while?

 

[DenG1]

I have recently had a new boiler fitted and once all the radiators were up to temperature I heard a tapping noise (like drumming your finger nails on a desk!) My new boiler is sited in the loft and I could only hear the noise upstairs. I deduced it was in the new pipes as it was very loud when opening the airing cupboard door. I left it for a week to allow the system to settle down and then called my installer back who identified it as expansion. He remedied this by slightly increasing the size of the holes from loft to airing cupboard ( he explained the pipes were 22mm and the holes he drilled out were 24mm). System now working with no noise at all.

 

[John506]

Could be as DenG said then.

Does it seem to come from any certain radiators?

 

[noisypipes]

All 3 bedroom radiators and the bathroom one seem to be as bad - clearly it's being transmitted from somewhere and the rads are amplifying it?? The pipes and rads are the existing system and haven't been touched - only the boiler is new. There was no noise before so presumably the pipes had plenty of room to expand - why would it be different now?Is the water from the new boiler hotter and making them expand more? Is it because the water is flowing in the other direction because the boiler posn has changed? Is the pump more powerful and what difference would that make? Surely you'd expect the biggest expansion (and therefore noise) when the system starts and is heating from cold not when the whole house and all the pipes are good and hot? If it is a pipe under the floorboards somewhere is there any way of finding where without taking up all the boards?

 

[DenG1]

If it was ok before, its surely got to be in the new pipework. Mine was where the pipes come down through the loft to the airing cupboard and as said in my previous post, the holes were cut too tight. But it sounded like it was something scampering along the loft (it could be heard in any room upstairs) but was extra loud in the airing cupboard. Get your installer back to check the new pipework, and hopefully it may be as simple to remedy as mine was - assuming it is expansion of course.

 

[TicklyT]

Are there any thermostatic valves fitted ?

It may be the flow rate on the new system is different, so they respond differently. Sometimes they get fitted the wrong way round, and nobody notices for years. Then a change elsewhere in the system can suddenly make them prone to 'chattering' instead of opening and closing smoothly.

 

[ctp]

are the trvs on the correct pipe, check which way the water is flowing,feel it getting warm and check the arrow on the valve.