Water hammer tried everything

[tryingtosavemoney]

Hi everyone,

I’m hoping to get some expert eyes on a water hammer problem that I just can't seem to shake.

Before posting, I tried all the classic remedies: I drained down the whole house to restore air pockets, installed a water hammer arrestor, and experimented with tuning down the flow via isolation valves. Unfortunately, none of it has reduced the banging noise.

It seems to trigger primarily when 1st floor hot tap basin and bathwater do not happen if we have just flushed the loo or turn on
cold water tap. To a lesser degree it happens to the washing machine, ie when taking in hot water slight ban/jolt noise.

The arrestor is fitted to the left of the stopcock under the kitchen sink toward the combi.
I've read up here and on the www about testing the combi to see if that was at fault and its not.
I've even reduced the incoming pressure from the street valve as well as tuning down the internal stops cock.

Since the basic fixes haven't worked, I'm trying to figure out what to investigate next. Could high incoming mains pressure be overpowering the system? Or am I likely dealing with a loose pipe somewhere deep in the structure that needs securing?

If you've solved a stubborn water hammer issue that arrestors couldn't fix, I'd love to hear what worked for you.

Its been ongoing for a few years and we can stop/limit the banging upstairs by turning on the cold tap, flushing the loo - but cant avoid the slight jolt noise
from the washing machine. At times the sink mixer tap hot water make a very faint jolt when turned off quickly.

Thanks!

 

[Wayners]

Isolate pipes and test.
So water between floors needs isolator so you can test ground floor and first.
It's likely to be the cold feed though.
You can isolate hot and test if no joy with cold water.
You can then find out where the noise is and fix it.
That's the plan.

 

[tryingtosavemoney]

Isolate pipes and test.
So water between floors needs isolator so you can test ground floor and first.
It's likely to be the cold feed though.
You can isolate hot and test if no joy with cold water.
You can then find out where the noise is and fix it.
That's the plan.

Appreciated.
How do I isolate - I'm ok with DIY but now quiet old retired for some years.
Easiest way please - I will also condier a plumber,
Its a 1969 build house, not the best for construction but better than those built in the last 30 years