What is that noise!?

[EastMidsTiler]

Hello everyone,

I was hoping some of you heating engineers could shed some light on an annoying noise my CH system has developed:

House & Boiler: 4 year new build, Ideal Combi boiler. Serviced every year, no problems before.

Problem: We don't run our heating super hot like some people but we do have it set to kick in on these colder nights we have been having. As the boiler reaches temp and kicks off, somewhere around our bedroom there is a dripping or knocking noise (very difficult to distinguish ) and I have yet to pin point where about it is.

At first I thought it was from outside as the gutter had moved slightly in the recent high winds but can definitely confirm it is only when the heating is on, or more specifically just as it turns off. Its almost as if there is a drip within a pipe. It's a constant sound but with the last few drops going through more quickly. Drip....Drip.....Drip....drip.drip.drip.drip. Stop.

If I'm not asleep before I hear it, I can't get the sound out of my head. Same in the morning if I wake a little early I will be in bed waiting for the alarm to go off all I can hear is this noise! The Mrs can hear it but she's able to tune it out and isn't particularly bothered. Apart from doing my head in, i also just want the satisfaction of locating it. One night I think its definitely coming from one wall, then the next night I'm convinced its another, then next its coming from the floor!

I bled the rads yesterday and one of them was particularly full of air and I was hopeful that was that but the noise was still there last night although not as bad. (but this could be as it was warmer the boiler wasn't in use as much)

I've been reading it could be trapped condensate? Up the pressure on the boiler?

Would a stethoscope help to locate it at all?

Any ideas please!?

 

[Chuck]

The noise you are hearing is pipework that is expanding/contracting and slipping/sticking as it moves. Search this site (or Google) for 'pipe noise' or 'slip stick' and you should find many threads asking the same thing and plenty of good answers.

 

[EastMidsTiler]

The noise you are hearing is pipework that is expanding/contracting and slipping/sticking as it moves. Search this site (or Google) for 'pipe noise' or 'slip stick' and you should find many threads asking the same thing and plenty of good answers.

Thank You, I'll have a search and google.

 

[WC1]

Can also happen at the point the radiator meets the wall bracket.

 

[EastMidsTiler]

UPDATE: It's still driving me mad! I can't seem to locate it at all. From one end of the room I'm convinced its coming from the opposite side and vice versa. Step out on the landing and I can still here it. Go downstairs in the night - can hear it.

Rads have been bleed and boiler re-pressurized.

My next step is to turn off the rads floor by floor (3 story house) and at least locate it to one floor and go from there. The problem is this the noise is only happening when the boiler is kicking in and out maintain temp during these cold nights. Unless I stay up at night or get up really earlier its impossible to hear during daylight hours.

This morning I turned both rads off in the bedroom and it did feel like the knocking/dripping sound was further away. But its so difficult to pin point I don't really know what i'm hearing or where from.

 

[Knappers]

If you find a solution that doesn't involve pulling up floor to get to all the pipes then let me know

 

[EastMidsTiler]

If you find a solution that doesn't involve pulling up floor to get to all the pipes then let me know

As a gas engineer can you tell me how the pipes are run on new builds? On my rads the pipes come out of the wall but I suspect they are ran under the floor and just up through the wall at each rad?

Obviously at some point the pipes are ran up the wall to get up a floor level, I suspect this is the point I need to find.

 

[Knappers]

If each rad has a drain point its likely they run up wall, if they run up from floor then they should come out of wall really low to allow air to find radiator but would normally just come straight out of floor.
If pipes are copper then a stud finder will be usefull, in wall they should have foil tape and will also be detected (but may not)

 

[EastMidsTiler]

If each rad has a drain point its likely they run up wall, if they run up from floor then they should come out of wall really low to allow air to find radiator but would normally just come straight out of floor.
If pipes are copper then a stud finder will be usefull, in wall they should have foil tape and will also be detected (but may not)

The pipes come out of the wall yes fairly low to the ground and the pipe that is visible behind the rads is plastic.

Got a new stud finder on order but not holding out much hope with that. Typical new build quality isn't the best and chances of pipes in foil slim to none.

Each night I've been turning off a different rad and trying to pinpoint it that way. I believe its happening on a return pipe

 

[WC1]

As above, no jokes, a younger person's hearing is much better than over 20's - especially for higher pitched noise.

If you haven't got one of them at hand get an automotive stethoscope for under a tenner delivered:

Silverline 154006 Mechanics Stethoscope - 320mm Automotive Tools for sale online | eBay

Find many great new & used options and get the best deals for Silverline 154006 Mechanics Stethoscope - 320mm Automotive Tools at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Or press a screwdscrewdriver handle to your ear and press the sharp end on to the pipe to find the source.

Like a listening stick

listening stick - Recherche Google

 

[EastMidsTiler]

As above, no jokes, a younger person's hearing is much better than over 20's - especially for higher pitched noise.

If you haven't got one of them at hand get an automotive stethoscope for under a tenner delivered:

Silverline 154006 Mechanics Stethoscope - 320mm Automotive Tools for sale online | eBay

Find many great new & used options and get the best deals for Silverline 154006 Mechanics Stethoscope - 320mm Automotive Tools at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Or press a screwdscrewdriver handle to your ear and press the sharp end on to the pipe to find the source.

Like a listening stick

listening stick - Recherche Google

Thank you for the suggestions. I've got a medical stethoscope I've ben using but so far haven't located it with that. I'm hearing the noise even with the stethoscope in but not through the stethoscope if that makes sense. To be honest I haven't actually spent that long looking, been knackered with work in the evenings. I'll have to upgrade to a mechanics scope if I don't have any luck soon.

I'll try the screwdriver tricks as well. not sure how effective that will be on plastic pipe but worth a try.

I'm just into my 30's but hearing the sound isn't the problem its figuring out where it is coming from over 3 floors without putting holes everywhere...to begin with at least. Its certainly not a high pitched noise, more of a low thud/drip. I'll see if my 5 yo is switched on enough to help!

 

[EastMidsTiler]

Thank you for the suggestions. I've got a medical stethoscope I've ben using but so far haven't located it with that. I'm hearing the noise even with the stethoscope in but not through the stethoscope if that makes sense. To be honest I haven't actually spent that long looking, been knackered with work in the evenings. I'll have to upgrade to a mechanics scope if I don't have any luck soon.

I'll try the screwdriver tricks as well. not sure how effective that will be on plastic pipe but worth a try.

I'm just into my 30's but hearing the sound isn't the problem its figuring out where it is coming from over 3 floors without putting holes everywhere...to begin with at least. Its certainly not a high pitched noise, more of a low thud/drip. I'll see if my 5 yo is switched on enough to help!

 

[EastMidsTiler]

Success! Incase anyone comes has a similar problem I was able to locate it. Funnily enough using just my ears rather than a cheap stethoscope.

I was able to locate it to a small area between living room ceiling and bedroom floor. Tried going through the floor but once pulled the carpets up could tell that would be a lot of work. So went through the ceiling plasterboard and straight onto the pipe in question. Perfect access.

The knocking was from where the pipe (plastic) was going through the joist. The return had a slightly bigger hole through the joist which I was able to pack out with a bit of well positioned felt and waited a few days...and silence.

Easy job to repair the ceiling and its all complete.

Thanks for all the suggestions.