loud clunking noise coming from the mains cold pipe All aspects of plumbing questions and answers, help, tips and information

[johnleadbeater]

every time the cold water is used a loud clunking sound comes from where the mains enters the house. have lagged the pipes under the floorboards and secured all the pipes but still get the clunking can you please help.

[rosebery]

Which cold water? The mains fed (presumably) kitchen tap or other taps which could be gravity fed (CW storage in roofspace) or mains? Which type of system do you have?

Does it happen with all taps?

Does it happen when you turn the tap on or off?

It sounds like water hammer but your answers will help narrow down the location.

[johnleadbeater]

its mains fed got a combi-boiler. it happens when the washer fills toilets flushed an on all the taps hope that helps its driving me nuts.

[rosebery]

Sounds like water hammer to me. This can simply be described as a pressure wave "bouncing" down the pipe when the tap / valve is closed quickly.

Normally I would say the first solution is to properly secure pipework but it seems you may have done that already in the area where the water hammer is occuring. Lagging the pipe won't make any difference in reality.

If it's occuring after your mains stop cock you could consider winding that shut a turn or two to restrict the flow but that will probably have an adverse effect on the water output at taps and doesn't address the root cause in any event.

If it's doing it on ALL taps / valves then it would seem that the solution is to fit a water hammer arrester as close to the problem as possible. This has a sealed pressure vessel containing air which absorbs the pressure bounce. Expect to pay anywhere between £ 15 and £ 30 depending for the domestic ones plus fitting. Don't go for the cheap fix which is a short(ish) length of copper teed off the pipe with a stop end soldered on the end so that it just contains air. Although, at first, this will work in the same way as the arrester in due time the air will escape and you'll be back to square 1.

You should do something about it as, apart from the irritating noise, every time it bangs it stresses the system and leaks can/will eventually occur.

Hope this helps

Cheers

Hope this helps

[simpleton]

sounds like water hammer, have a look round at your pipe work and make sure its all clipped securely. The quickest and easyist way to remedy it would be to turn your stop cock down a touch if its bothering you

[prbaxter]

i've had this before. it was happening on the bathroom sink but no where else. It was water hammer. What i did to fix it was to close the service valve slightly for that one sink to limit the pressure at the tap - this stops the tap valve from vibrating and sending the shockwave through the system.

If its all taps, then reduce the pressure of your main water supply slightly. If this makes all other taps severely reduced in pressure, then see if there are service valves that you can open up a bit for each one.

The service valve (or ballofix as they are known) is usually a straight connector on the pipe with a screw in the middle. Having the line on the screw head running parrallel with the pipe is fully open, having it horizontal to the pipe is fully closed. there's only quarter of a turn in it. Some have little plastic taps on in place of the screw.

[rosebery]

prb wrote: "It was water hammer."

I think we established that.

prb wrote: "If its all taps, then reduce the pressure of your main water supply slightly."

I thought he said it was all taps. Just winding down the stop cock treats the symptom not the cause IMO.

[johnleadbeater]

[quote="rosebery"]Sounds like water hammer to me. This can simply be described as a pressure wave "bouncing" down the pipe when the tap / valve is closed quickly.

Normally I would say the first solution is to properly secure pipework but it seems you may have done that already in the area where the water hammer is occuring. Lagging the pipe won't make any difference in reality.

If it's occuring after your mains stop cock you could consider winding that shut a turn or two to restrict the flow but that will probably have an adverse effect on the water output at taps and doesn't address the root cause in any event.

If it's doing it on ALL taps / valves then it would seem that the solution is to fit a water hammer arrester as close to the problem as possible. This has a sealed pressure vessel containing air which absorbs the pressure bounce. Expect to pay anywhere between £ 15 and £ 30 depending for the domestic ones plus fitting. Don't go for the cheap fix which is a short(ish) length of copper teed off the pipe with a stop end soldered on the end so that it just contains air. Although, at first, this will work in the same way as the arrester in due time the air will escape and you'll be back to square 1.

You should do something about it as, apart from the irritating noise, every time it bangs it stresses the system and leaks can/will eventually occur.

Hope this helps

Cheers

Hope this helps[/quote]

[johnleadbeater]

many thanks rosebery for all your help sorry about the delay in replying got a plumber booked to sort it out. thanks again.

[scarletterry]

HI I HAVE THIS PROBLEM ALSO,IT HAPPENS ON ALL TAPS, UP AND DOWN,HOT AND COLD,THE TOILET,SHOWER,WASHING /DISHWASHER,HAVE TRIED TO LOCATE WHERE ITS COMING FROM BUT WHEN YOU ARE DOWNSTAIRS IT SOUNDS DOWN THERE, WHEN YOU ARE UPSTAIRS IT SOUNDS UP THERE HAVE TRIED CLOSING MAIN STOP COCK A LITTLE THAT DOES NOT WORK .