Where is the air coming from

[Tuli]

Hi, I've had a water hammer / knock. I've done the switch mains off - switch all taps on - switch main on - switch taps off procedure. It worked, no water hammer. However, few moments later, I switched on the tap in the upstairs bathroom (it's a 3 storey victorian property) and lots of air came out / water sputtering, when I switched the tap off, water hammer was back! very annoying.

Any ideas of where is the air coming into the system?

Thanks!

T

 

[Chuck]

Any ideas of where is the air coming into the system?

The procedure you followed introduced the air. While it was in the system it acted like a spring/damper and suppressed the water hammer. Once the air was purged from the system the hammer returned.

 

[Lou]

How can the op rectify it?

 

[Tuli]

Hi, thanks for your reply. I just followed the instructions on several website about how to get air out of your system... I guess that was the wrong thing to do?
Is there anything else I can try?
Thanks again,
T

 

[Chuck]

Is there anything else I can try?

There are a couple of types of water hammer. To be helpful we need a bit more information, i.e. when does it occur and what tiggers it?

 

[ShaunCorbs]

Simply needs to clip there rattling pipes

You could fit a shock arrestor to help the problem but this is more of a bandage than a fix

 

[Tuli]

It occurs when a tap is switched off. I found that when I reduce the water pressure the hammer disappear too but it's not a great solution :/

 

[Chuck]

It occurs when a tap is switched off. I found that when I reduce the water pressure the hammer disappear too but it's not a great solution :/

That type of hammer is often due to the pipework not being clipped firmly and at sufficiently frequent intervals. For 15mm pipe, clips should be no further apart than 1.2 m on horiztontal runs and 1.8 m on vertical runs. More detail here:

https://copperplumbing.org.uk/sites/default/files/content_attachments/fixing-copper-tube_0.pdf

 

[Tuli]

Thanks everyone. I guess there is no solution then? I mean, from what I can tell most/all pipes go inside the walls and behind cupboards, how would I find where they need to be clipped
Sorry if this sounds stupid but I wouldn't even know where to start

 

[Warmiger]

Hi

Also alot of water hammer noises are also caused by a bad gland or valve jumping.
You could have a bad cartridge in a tap. You can normally feel the tap vibrating.
It might be easier to get a professional in. Check the incoming pressure and if need be install a pressure reducing valve with a gauge. It can sometimes improve things and you can also see if the stop tap gland is jumping affecting the whole property. Hope this helps.