Water hammer

[Symposium]

Any tips for curing water hammer before I call out a plumber again? I had some work done on my bathroom taps and the pipes are now rattling whenever you shut them off. I've already tried turning off the mains and draining the system, (a lot of air came out the bath taps!)then turning it back on again. However, although it seemed to improve at first, it's back doing it again. Seems to be just on the hot taps. Anything else I can try myself ? As I've already paid 2 lots of plumbers a small fortune for not very good work as it is!

OMG, the dreaded water hammer. Very difficult to diagnose . We had this, it just started with the bath tap, intially had that changed, no joy - we have sevveral plumbers out and stuff fitted but did not make a difference then we had three taps changed and it stopped

In your case, poss easy to diagnose as you've had new works done so they will look into that.. Good luck

Upuntil that point, we'd never heard of "Water Hammer" - reading your post brought back memories

It may be an airlock. We had something similar and so connected the cold tap to the hot tap and turned them both on and the cold forced water back into the hot tank and seemingly cured the problem.

Note: I'm NOT a plumber and for all i know I could have blown the house up. Fortunately I didn't.

You got a pressure regulating valve fitted to your system do you know? If you do, turn the pressure down on this - easy job with either screwdriver or the built in dial. If you don’t then fitting one could resolve things as the mains pressure could be too high which is causing significant fluctuations in pressure.

If you have one fitted it will be somewhere just before your boiler on the mains fed side, and will look something like the below.

https://www.bes.co.uk/adjustable-pressure-reducing-valve-15-22mm-22301/

You can also buy a water hammer arrestor too if one not fitted.

Thanks for the suggestions. I'm sure we don't have a pressure regulator valve. It's a very old house and the pipes have always been a little noisy but this is definitely worse than usual and I can see the pipes vibrate where I'm sure they didn't before. I've tried draining the system again and although it seems to work for a little while the hammer comes back within hours.

The age of the house doesn’t mean you won’t have had a PRV fitted at somepoint in the past. I put one in on our system a couple of years ago - 1896 Victorian terrace. If I were trying to DIY fix this then that would be my first port of call. If your mains pressure is high which it might if you say that it has been happening a while then knocking the pressure back may well fix the problem. It would enable you at least to set the pressure very low and then dial up from there to test. It would mean you cutting pipes to insert the device, so if you can’t do this then you’re gonna need a plumber anyway so may as well call the expert.

FYI#

We've had pressure reducers etc everything done in our home and some of the taps. It is very diffuclt to diagnose as i said unless you've had new works completed, so easy to ID. Changing three taps did the trick but it can be a massive mystery