Water hammer

[mfgs]

I went to look at a job today and there is really bad water hammer in a flat when any hot or cold tap is opened or closed. Its a mains fed system, combi boiler. Its strange though as it will be really bad for 5 mins if using and water, then after that nothing. The guy said it happens randomly, sometimes its fine for a full day and others its bad all day. He also said it sometimes happens when no taps are opened, no washing machine is on and the toilet hasn't just been used.

Any ideas where to start? I'm thinking of replacing the stopcock to start with and then go round isolating taps etc one at a time?

 

[rocketmanbkk]

How about fixing a shock arrestor?

 

[mfgs]

I have fitted one before when trying to cure water hammer, it made it better but did not resolve the issue. I would rather find the cause and sort it if possible.

 

[julesverne]

How about a prv after stop tap

 

[julesverne]

Could it be the random time it happen due To usage in the street from other neighbours affecting flow and pressure.

 

[Last Plumber]

I think you are right to start with stop tap.
I'd check the pressure and possibly fit a regulator (if it's high)
Maybe a shock arrestor.

 

[Last Plumber]

I think you are right to start with stop tap.
I'd check the pressure and possibly fit a regulator (if it's high)
Maybe a shock arrestor.

 

[mfgs]

The pressure I don't think will be the sole cause. There are 4 flats in this building and all fitted out exactly the same and they aren't having the same problems. So I am thinking there must be a tap or valve at fault somewhere.