Water pipes make noise on closing the tap

[Ch. Rajinder Nijjhar Jatt]

Hi,

Recently when we open our water taps and close suddenly it makes noise. It was not making before we had changed central heating system to Combi boiler.

What could be the reason please?

Rajinder

[BigWallop]

Pipe clips may have been taken off, and this can cause the pipes to rattle. It may also be the water pressure has been turned up from what it was before the boiler was installed.

You could try turning the mains stopcock off "slowly" until this stops happening. Do a little at a time, and keep checking with the taps. If this helps, then test that the boiler is still working properly, and is still supplying enough hot water for you.

[Kenny of the Fells]

Had a similar problem last week - banging pipes and a combi that wouldn't fire up unless the hot tap was on full (and then the flow was so fast it didn't get particularly hot). I thought this was a boiler fault and when Mr Repair Man looked at it he decided to *open* the stop c*ck. Now the boiler is fine and no banging pipes either. No, I can't figure it out...

KotF

[Aidan]

Water hammer. Search the archives.

The amended system is working at a higher pressure, & is probably supplied through a 1/2" water main. When you shut the taps suddenly, there's a long, moving column of water, going back to the water main, which is brought to a halt with a bang..

[John Rumm]

Your combi will supply hot water at mains pressure, which compared to your previous setup may be a significant rise. This can result in far more shock and water hammer being expierenced in the pipework when you stop or start the flow suddenly.

If it is a serious problem then you may need to fit a shock arrestor to the system. This is basically a small expansion vessle that is designed to absorb some shock from the water.

Have a look at part number 11355 on

are easy to fit, and can go somewhere out of sight on a hot (and cold if required) water pipe.

[Ch. Rajinder Nijjhar Jatt]

Hi,

It was the Mains stopcock that was open less than required. I opened it full and it stopped.

Thanks for the help.

Rajinder

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[Hugh]

'Water-hammer' - you can buy a valvre to cure this - try builders merchant - cost around £15 - that's all I know - read once you can put in a parallel pipe in the system to cure it - just a short run of perhaps 12 inches. It's caused by ,for example, WC cistern valves - common problem.

[Ch. Rajinder Nijjhar Jatt]

Sorted it out. The mains valve was part open and caused problem. Opened it full and all is well.

Thanks.

Rajinder

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