CH Boiler Enclosure

[Rob]

I have a newly fitted Ideal combi boiler. I'd like to enclose the boiler in some way, partly for appearance, and mainly for noise - it gives out a roughly 500Hz hum that seems to come from the pump. This has a strange effect round the house - it seems to get everywhere. The installer tells me it's all working within spec, and the noise isn't unusual.

Should I be looking at mass (18mm MDF say?), any design tips etc? It's too big (need 1m high, 40cm depth) for a standard kitchen cabinet. Besides which I'd like something more likely to suppress the noise.

Thanks, Rob

[Andy Burns]

Isn't it more likely the noise is propagating via the pipework, so building it in will only quieten it locally?

[Roger Mills]

You need to have a careful look at the boiler installation manual. It probably needs a defined amount of ventilation - which would preclude boxing it in completely.

If the pump noise is getting all round the house, chances are that it is being transmitted through the pipes rather than through the air - in which case boxing in wouldn't help.

[Rob]

Yes, I have - it's fine, allowing it to be boxed in with very tight gaps.

Yes, that's the odd thing. If anything it sounds louder in the bedroom directly above. I can't seem to detect a sound or isolate the effect of the pipes though, so I'm left with having to do this one step at a time. I'd guess there's no easy way of minimising the effect of the pipes though.

Rob

[Dave Liquorice]

Make sure they are not solidly fixed to or pressing against any part of the building. Loosen any clips clips, make sure and holes they go through have clearance all the way round and through. If a gap needs filling to prevent drafts do it with something soft and compliant like rockwool rather than plaster, filler or expanding foam. I suspect that even silicone sealant would be too hard and transmit the vibration.

Use a stethoscope to track which bits are vibrating more than others. By stethoscope a long screwdriver with the handle end pressed to your ear works well whilst probing with the driver end against things.

[Rob]

Thanks for that, will do.

Rob

[Ronald Raygun]

500Hz is pretty high-pitched (a little sharper than the B above middle C on a piano). I'd call that more of a screech than a hum. Or did you mean 50Hz?

If this is a replacement for a previous boiler which did not have that problem, then it's a new problem which he has caused, and I wouldn't let him fob you off like that. As I see it he has supplied something which falls short of being satisfactory, and it's up to him to sort it out.

[Rob]

More a ringing, I estimated the 500Hz tone with Audacity audio prog.

Mmm, I find this tricky. In the day it doesn't sound too bad, but quiet of night it really is quite intrusive, what I'd imagine a variety of tinnitus to be like. And certainly not the type of thing I'd like to sleep to. In this room, 2 floors up, I can hear it but it's more an echo and far less intrusive.

Rob

[chudford]

Does the noise occur when the boiler is firing or when only the pump is running?

If it is when the boiler is firing it could be the fan which may have a secondary flimsy metal cooling disc which is rubbing. This will make a high pitched sound.

[Steve]

Does the noise occur when the boiler is firing or when only the pump is running?

If it is when the boiler is firing it could be the fan which may have a secondary flimsy metal cooling disc which is rubbing. This will make a high pitched sound.

Don't box it in too tightly or in a way access cant be gained, being an Ideal if wont be long till it needs TLC

[PeterC]

A low(ish) frequency will be audible a certain distance and hardly so a couple of feet further and so on. I used to stay in a cottage that had an old extractor fan in the loo; it was loud (at night - not too noticeable during the day) at the foot of my bed, couldn't really hear it at the middle of the bed, then loud again by the pillow - sod's law, of course.

[Rob]

When the pump's running. Once temperature is reached, or hot water is switched off, the pump, and the noise, continue.

It's got a 5 year guarantee so that'll be their problem ;-)

But yes, I was thinking a screwed front panel, and hinged smaller panel to access the controls.

I've had a board up and found one troublesome pipe - move the pipe and the pitch changes to the point the noise can't be heard any longer at the other end of the house. So that's progress. I'll try and rule out this resonance thing first I think - more boards up etc.

Rob

[stuart noble]

We had trouble getting used to the fan on a WB. It seems to expel the fumes halfway across next door's garden, so I suppose the airflow alone would create a whine. We did get used to it eventually though.