Water Hammer dilemma - particularly regarding costs

PostHoc25

https://forums.moneysavingexpert.com/discussion/comment/81993457#Comment_81993457

lol. Yup, good old British passive aggressiveness will save the day, no doubt!

PostHoc25

Gargh, so another 45 min plumber visit and not much has changed except now they are 90% convinced it is a loose pipe issue and flooring will need to come up. LL is now trying to ascertain if we are the only flat with the issue or if it could be a freeholder/building management issue. I suspect not as it is most likely concerning the supply directly into my flat and not coming into the whole building. Also having spoken to at least 2 other residents on same floor as the neighbour who hears the hammer from my watery things, they have no plumbing noises coming through from the properties above. So I think it is isolated to my flat, but we still don't know when it started.

Was it the install of the washing machine a few years back that started it all, I wonder. But if so, would that make hammer occur from everything else when the washing machine isn't being used - shower, mild from toilet and of course the roaring kitchen sink?

I've had no reply from previous owner yet when I asked her if during her years here noise was always bad or starting occuring at some point, so who can say.

Just met local water company who came out and did a pressure test. They read it as 4, very normal and not high enough that they felt pressure would be causing the issue necessarily.

So does this leave us fitting a shock arrestor on the washing machine and potentially the shower too? And perhaps a PRV on the supply coming into my flat by the stopcock in the communal hall? Water co techs also suggested it could be a worn out jumper in the stopcock coming into my flat, hence everything being affected. It really is a whole system issue and although reducing the flow has helped a little. By grabbing the pipes they could reach under the sink today, the plumbers were able to dampen the sound further. The roaring kitchen tap does not seem to change though.

I have suggested my LL gets a second opinion at least before committing to floors being ripped out to fully access and secure pipes in kitchen. Not sure if she will. She also needs to check her insurance, so for the neighbour downstairs, nothing has improved after today's visit which is not good. She has threatened legal action and it's getting a bit angtsy to be honest. Google suggests if floors need to come up she should allow us 4-12 weeks to complete the work, before pursuing legal action - council noise complaints etc. We were first notified the second week of March this year, so it has been about 10 weeks already.

All in all, not the best.

WIAWSNB

4 bar is certainly 'high', tho' wouldn't normally be considered excessively high - ie most plumbing installations would cope without undue noise and issues.

Would tweaking it down to 3 bar or slightly below improve this? I'd say, almost certainly yes.

You have two issues going on - one is the hammer, and the other is the roar. Put them together, and that suggests more than a loose pipe.

Ok, you may have a looseish pipe that likes to 'hammer', but you also have roaring taps, and that has now't to do with the hammer. So, after they rip up your floors and clip that pipe to hopefully stop the hammer, you'll still have the water-flow noise.

Could you try summat - place a pan under your kitchen cold tap, and turn it on full for 10 seconds. Measure the number of litres, and 'times it' by 6. Let us know the figure. (I'm hoping your kitchen cold tap is a normal type and not restricted.)

PostHoc25

it's almost 3 litres in 10 seconds (2l 950ml) so x6 is 18 litres give or take. In terms of it being normal or restricted - no clue how I'd know :-)

PostHoc25

https://forums.moneysavingexpert.com/discussion/comment/82004729#Comment_82004729

Further to the previous water flow I gave of approx 18 L per min, it has been suggested that the roar is a distinct issue for the kitchen tap. Plumber viewed it as new but it was installed in 2018 so 8 years old now. It is this one:

Could it be responsible for the roaring we are wondering now!

WIAWSNB

Unlike the 4 bar pressure which can be described as 'solid' or even 'highish', 18 litres per minute flow rate is merely 'good', 'decent' or 'adequate'!

It's a nice flow rate, but not exceptional, and shouldn't be considered a problem in any way. It, by itself, shouldn't be responsible for tap noise.

The tap itself is also a decent make, is suitable for both high and low pressure systems, so I wouldn't expect it to be restricted in any way. So I'm assuming that your measured 18lpm flow rate is pretty accurate.

Can you confirm - the 'roar'/noise is created by this tap only?

Is there a bath in the flat? If so, please repeat the flow test using only the cold tap, full on as before.

PostHoc25

https://forums.moneysavingexpert.com/discussion/comment/82005294#Comment_82005294

Yes, it's only the kitchen tap that roars. The bath is probably used once every 2-3 months so doesn't really come into play. The shower I posted previously does have bad water hammer but no roaring. Angling the tap at different intensities whether hot or cold water does cause more noise in my flat as well as altering the pitch and volume of the roar she hears. Quite impressive if that little tap itself is to blame for the roaring :-)

And the plumbers did turn down the flow a bit so that probably tracks with your description of 18L flow rate. We are going to test the taps in our neighbour's flat soon (it has been empty for a while so we want to rule out any additional hammer that may also travel downstairs from their pipes as they are so close. I suspect it is just my flat, but deff worth checking before floors are pulled up!

WIAWSNB

Confirm, please - they did or did not take a flow rate reading? (They'd have used a clear cylindrical gauge for this - water aimed in the top, and it comes out t'bottom, with a lpm scale on the side.)

Ok, please do this - open the mains stopcock fully, counting the number of turns this takes so you can return it there. Take separate flow rate readings at the sink and bath colds. For the sink, also try it with the tap in its mid position, so both hot and cold are flowing.

Does the bath have separate taps? Use only the cold. Full on each time.

Then return the stopcock to its partially closed position.

WIAWSNB

The pipe the plumber reached for which slightly dampened the hammer, could we have a pic of it please, and where he stuck his hand? Ta.

PostHoc25

https://forums.moneysavingexpert.com/discussion/comment/82005513#Comment_82005513

I appreciate the support on this but can't adjust the stopcock as LL has given strict instructions not to to tinker since plumber adjusted things because second opinion plumber is due out soon. Additionally I don't want to risk making things worse for neighbour as his adjustments have taken the edge off the banging a little bit. My kitchen is tiny and I was downstairs in neighbour's flat while pipes under sink were held so I have no clue which are deemed to be the issue unfortunately. Not helpful, I know.

However, I have just spoken with Bristan about replacing the cartridge in the kitchen tap specifically to address the roar and forwarded info to LL, so may try that route first.