Water hammer

[ash_scotland88]

We have water hammer when anything turns off, unless it's a tap slowly. I'd need to have a crawl space investigation but the main incomer is secures solid, so don't think it's a lose pipe, unless it can vibrate from somewhere else?
The main comes up and splits almost instantly. One up to the attic, the next goes down under the floor. Up in the attic it drops from the 22mm-15mm then increases back in size, this then goes back down to first floor and then to bathroom under the flooring.
Could this reduction in pipe size be the cause?
Anything else to look out for apart from lose pipes?

 

[200sols]

Have you added anything new? Taps etc? Has it come on suddenly?

Any idea how high your water pressure is?

Do you have a tap style stopcock? Sometimes the washers in these can move, try closing it a bit and see if it stops. Replace with a lever ball valve anyway.

 

[ash_scotland88]

Its always been here in the house since we've been here. Been working from home a lot recently so annoying me more so.
Yes to tap style stopcock. I actually think we have low pressure tbh, hot pressure to me could be higher (i know this is a negative of combi-boilers) but even cold could be a tad higher flow/pressure.

 

[Bug One]

I fitted a new kitchen tap, and now my wife has the ability to 'slam' the tap from 100 to fully shut almost instantly.

I shudder every time I hear it, and the effect it has on the pipes.

 

[The_One]

Get a pressure reducing valve and a mini expansion vessel fitted on the cold mains

 

[PlacidCasual]

Long straight pipe runs, high water velocity and fast closing valves will cause water hammer. An expansion vessel on the problematic pipe run will eliminate the problem. A few bends also helps as the water changing direction breaks up the momentum.

 

[sja360]

Has it always happened?
The size reduction is odd, if it goes back to 22mm why did they bother with the reducing piece? That would increase the pressure as it goes down to 15mm.
I'd suspect it is that causing the water hammer

 

[ash_scotland88]

Always happened since we've been here, although I think getting worse. It's neighbours I feel sorry for, they must hear it too and wonder why we slam doors every so often in a 10minute period as the washer goes.

I'll get some pictures up.

Photo was taken a while ago when I was in that corner of the attic last, all un-used pipes are now pulled up.
My knee is hiding a short peice of copper to an end stop. Reading up on water hammer this could also be a cause of the hammer. I've also secured that section of pipe down and have no idea what way it flows either. without investigating further.

https://ibb.co/6DzmqtW

 

[The_One]

stop worrying about the pipes and fit a mini expansion vessel and even better a pressure reducing valve

 

[Usel]

I had a slight water hammer effect and it was the ballcock for the water tank in the loft. It was still working properly and the tank wasn't over filling but would take an age to stop filling up the last little bit.
Replaced the ballcock and it stopped.

 

[ash_scotland88]

stop worrying about the pipes and fit a mini expansion vessel and even better a pressure reducing valve

I get what your saying but that's then giving me a yearly (or whatever) maintenance issue instead. Surely I should be best to try and fix the problem first?

 

[The_One]

yes fitting them is fixing the problem and there is no ongoing maintenance required

 

[ash_scotland88]

yes fitting them is fixing the problem and there is no ongoing maintenance required

I thought they had to be refilled every so often?

 

[Steampunk]

I thought they had to be refilled every so often?

I think you can get ones that have a valve on top and are zero maintenance. They sort of fill themselves.