Water Hammer issues / Maybe undersized pipes

[mstizomad]

Hi,

We have just done a large amount of plumbing ourselves in our renovated bungalow.

It's all been done to a good standard in terms of soldering etc and it's all in copper.

We have use 15mm pipes for the entire cold water system as that's what it was originally before being wripped out and redone AND because it's a 15mm pipe connected to the mains pipe that is concreted into the ground, with a 15mm stop cock etc, so i didn't see the point in using 22mm.

We have average water pressure, doesn't seem too high or too low, but i will get it tested properly soon.

However, we are getting water hammer mainly caused by the basin and sink taps being turned on or off.

I have instaled mini water hammer arrestors near the toilet and the washing mashines, which stopped them caused water hammer, but i installed one near the basin and it made no difference, maybe even made it worse!,

Also, all the appliances are being supplied at mains water pressure, with no cold water tank or anything.

Would a 25L expansion vessel help to stop water hammer?

And do you think my pipes are undersized?

If worse comes to it, i am willing to redo all the mains runs of pipe in 22mm, right up to just before the Kitchen and Bathroom, but they would still be fed from a 15mm pipe coming out the ground, so i don't see the point really.

Thanks

 

[dilalio]

Can you upload a video with sound of the issue?

Have you provided enough clipping for the pipework?
Have you lined any notches in joists with felt lagging where pipes pass through? Are your taps high or low pressure? Do toilet inlet valves have high pressure inserts in them?

 

[AGAS]

make sure your stop cock is fully open .

 

[Newboy]

If you're getting water hammer when you open an outlet (as stated in your OP) it's worth checking that you haven't fitted a stopcock back to front.

 

[mstizomad]

Can you upload a video with sound of the issue?

Have you provided enough clipping for the pipework?
Have you lined any notches in joists with felt lagging where pipes pass through? Are your taps high or low pressure? Do toilet inlet valves have high pressure inserts in them?

Hi everyone,

Thanks for all of your responses.

All of our taps are suitable for pressure up to 8bar, and i don't think our pressure is as high as that, but i will get a pressure test device tomorrow.

The pipes don't go through any joists or walls.

Yes there is a valve in the toiley inlet, however the toilet is no longer an issues, as the water hammer device under the inlet has made it very quiet.

On further investigation, the bathroom basin is by far the worst culprit, the shower being the second worst.

The kitchen sink cuases water hammer, but only very mild.

All the pipework is quite solid, there are no spans between clips of more than 1m, and no areas that seem to allow serious movement.

What is the recommended max distance between pipe clips?

I cannot work out also, why my arrestor device underneath the basin, makes things WORSE!

Yet my two arrestors elsewhere have worked very well.

Thanks

 

[Hugh Jaleak]

Are you sure you are describing this properly? Water hammer is when a washer or jumper in a valve, vibrates akin to a reed in a musical instrument, and the resulting howling noise reverberates back through the pipework, reaching a crescendo as the valve finally closes off.

A thump or clunk as a tap closes is usually a sign of loose pipework somewhere which is moving with the kickback of pressure as a tap suddenly closes.

 

[MJGas]

Turn the tap off slowly. Does it still do it?

 

[mstizomad]

Hi,

Yes it's only over a single bang noise, as opposed to continuous hammering.

If i turn the basin tap off very slowly, it's doesn't do it at all. But even turning off at a medium pace causes a large bang.

Should i consider replacing those taps for ones with a 3/4 inch bore instead of 1/2 inch?

OR i could install a pressure reducer valve underneath the basin?

I have noticed there is ONE area of mildly loose pipe work at the other end of the house, and using the Basin taps causes a bang here, despite being 30 metres of pipe away.

 

[jeff the gasman]

Hi,

Yes it's only over a single bang noise, as opposed to continuous hammering.

If i turn the basin tap off very slowly, it's doesn't do it at all. But even turning off at a medium pace causes a large bang.

Should i consider replacing those taps for ones with a 3/4 inch bore instead of 1/2 inch?

OR i could install a pressure reducer valve underneath the basin?

I have noticed there is ONE area of mildly loose pipe work at the other end of the house, and using the Basin taps causes a bang here, despite being 30 metres of pipe away.

Make sure your stop taps, both internal and external are fully open and you have no dead leg pipework.
A single thump indicates a stop tap jumper hitting its seating,
It doesn't matter about pipe size if you are happy with the flow from the taps.

 

[mstizomad]

Make sure your stop taps, both internal and external are fully open and you have no dead leg pipework.
A single thump indicates a stop tap jumper hitting its seating,
It doesn't matter about pipe size if you are happy with the flow from the taps.

Hi, thanks for the advice.

We have TWO stop taps where the water comes into the property, one new and one old, pretty much next to each other.

The older one has a VERY slow drip on it, so i will definately look into changing the washer OR replacing the entire stop tap.

I will also look at the external stop tap, however i will need to get one of those keys.

The bang noises is also predominately right near the stop tap area.

Cheers

 

[Steelmasons]

Hi, thanks for the advice.

We have TWO stop taps where the water comes into the property, one new and one old, pretty much next to each other.

The older one has a VERY slow drip on it, so i will definately look into changing the washer OR replacing the entire stop tap.

I will also look at the external stop tap, however i will need to get one of those keys.

The bang noises is also predominately right near the stop tap area.

Cheers

Employ the services of someone who has a clue as to what they are doing.....best advice so far...

 

[AGAS]

make sure your stop cock is fully open .

open them all fully and the problem is probably sorted , if you got someone in early doors just imagine all that time you could off saved messing about trying to sort this problem.

 

[dilalio]

Two stopcocks! In series or parallel? Do you have 2 incoming mains?

 

[mstizomad]

Two stopcocks! In series or parallel? Do you have 2 incoming mains?

Hi,

They are in series!, We only have one incoming water main as standard. I've attached a photo:

I think the previous owner of the house found that the old stop tap was starting the leak / fail and rather than replacing it, he just put another stop tap on the pipe!

The old stop tap has a BAD leak that would fill up a pint glass in hours, i put in some PTFE and tightened the top knut until the leak was reduced tiny drip that doesn't even maker a puddle,

Cheers

 

[mstizomad]

All the pipework in this area is also really loose.

I'm just going to cut out everything and completely redo the whole area with a new straight run in the corner, a new stop tap and a water hammer arrestor just for good measure.

I have also noticed that we are getting vibrations and small bangs in this area, when our neighbours are using their water.