Hot water pipes clanging when hot water turned on/off

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Cheers for your help - easier to put up with now that we know turning on cold water before hot tap in bathroom removes all of the hammering

You are a very kind man, so thank you.

mexican_dave

I realise OPs new bathroom could offer a solution to the problem, but I don't think it's been said in this thread, that turning down a stop-tap mainly reduces "flow rate", so when all your sanitary fittings' taps are OFF the pressure builds up quickly again, whereas a pressure reducing valve (PRV) on the incoming cold main (yes, it's bulky) has a mechanism to let water through at a given pressure. Does what it says, see PRV example https://www.toolstation.com/made4trade-pressure-reducing-valve-and-gauge/p44160

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@mexican_dave

Thanking you.

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Another thought and update. We are changing the bathroom - We have quareter turn, bath taps with a shower mixer. I changed the washer o this a couple of years ago and agai changed it today
It's made a 85/90% difference to the nosie and the on/off water much smoother

I got a pack of 4 washers and found the remaining three and replaced like for like old one was worn

The diameter is 25mm. On the washer by HAYES I think it states its a 3/4 inch washer. But like I said it measures a fraction under 25mm ie one inch

I tried to put the old one and new one in but there was no water coming so put one new one

Mu question is Wickes appears to have a slight thicker bath tap washer but it states 19mm which is 3/4 of an inch

When measuring for these do the not measure, take into account the whole diameter?

This is the one by  PRIMAFLOW  looks better and a better shaped IMO

https://www.wickes.co.uk/Primaflow-Bath-Tap-Washers---19mm-Pack-Of-2/p/420052

I'm thinking of going to our local Heathrow branch around 7 and will try it tomorrow

Any ideas again ?

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Btw which  end goes up, ie the side you can see as you place it in the tap ad put the screw o to hold and see the head of the screw

mexican_dave

The "rubber" tap washers are intended to be flat both sides (as your Wickes link) but for manufacturing reasons they often have a smooth slightly rounded face on one-side and a plain flat face on the other. Maybe it's just me but I put the very flat face against the tap-head so the more rounded face goes into the tap body and is the sealing face.
Maybe it's a British Standards "allowed deviation" thing (I dunno) but there seems to be variation in tap-washers. If you peep into the body of the tap to look at where the washer seals, there is a "shelf" maybe 3mm wide all around that your washer seals against, so some variation does no harm.The washer only has to cover part of the "shelf" all round  if you get my meaning.

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cheers.......

ThisIsWeird

UnsureAboutthis said:

We have quareter turn, bath taps with a shower mixer. I changed the washer o this a couple of years ago and agai changed it today
It's made a 85/90% difference to the nosie and the on/off water much smoother.
I got a pack of 4 washers and found the remaining three and replaced like for like old one was worn
The diameter is 25mm. On the washer by HAYES I think it states its a 3/4 inch washer. But like I said it measures a fraction under 25mm ie one inch
I tried to put the old one and new one in but there was no water coming so put one new one
Mu question is Wickes appears to have a slight thicker bath tap washer but it states 19mm which is 3/4 of an inch
When measuring for these do the not measure, take into account the whole diameter?
This is the one by  PRIMAFLOW  looks better and a better shaped IMO
https://www.wickes.co.uk/Primaflow-Bath-Tap-Washers---19mm-Pack-Of-2/p/420052
I'm thinking of going to our local Heathrow branch around 7 and will try it tomorrow
Any ideas again ?

I'm a bit confused by your post. But I'm sure you understand there's a world of difference between quarter-turn taps (ceramic valves which need to be replaced as a whole valve insert) and conventional taps which are multi-turn and use rubber washers?

But you say, "We have quarter-turn, bath taps with a shower mixer. I changed the washer in this a couple of years ago, and again changed it today". Could you explain, please?

Anyhoo, it has helped! That's good, and not unusual, as worn or loose rubber washers can vibrate in a powerful water flow, and the drone it makes is it resonating.

With a conventional, M-Turn, tap which uses rubber washers, the thickness is quite important, and there's a limit to how thick, or how thin, it can be to work properly. Turning the tap handle 'screws' the washer down until it seals off the flow, and this movement is usually only a few mm, especially if the tap mechanism is getting stiff. If you put in a too-thick washer, then it'll effectively be almost always closed off, so the tap won't work. A too-thin washer might have the tap failing to shut the flow off properly, with the tap mechanism having to 'screw' out too far.

Anyhoo, you are au fait with swapping them, but there's an issue with the washer sizes? A reference to 3/4" will likely not mean that actual size of washer, but the fact that it's for a 'bath' tap, with 3/4" tails, whereas basin taps will be referred to as 1/2".

The important dims are the washer diameter, and thickness. There will be some flexibility on these, but not excessively so, like adding an extra washer to the thickness :-)

Take the tap inserts with you, and the old washers - that'll be your best bet for correct replacements.

If you are still struggling after tomorrow morn, could you post a photo of the round plate that holds the washer, and some dims?

(If you weren't going to replace the taps at some point in the known future, it's often worth giving the screw mech an overhaul too, adding a good dollop of sili grease - sooooper-smooth.)

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Thanks TW
I got the new ones in the link last night. They are a bit thinner, EB 0.3mm approx but same diameter, ie 3/4" but 1 inch in diameter.  Changing the rubber last night made a small difference but noise heard downstairs is still the same and upstairs its about 80% reduction  or a bit less as this is how it feels

I will try the new washer this morning may try sticking both in

Failing all that, I will call a plumber out and ask the guy if there is any charge and how much before her comes to look and if he does nothig this time. Best to be clear beforehand imo.

The taps are a quarter turn, like ones below with rubber washers
https://www.victorianplumbing.co.uk/lancaster-traditional-bath-shower-mixer-with-shower-kit?campaign=googlebase&s_kwcid=AL!15853!3!!!!x!!&gad_source=1&gclid=CjwKCAiAlJKuBhAdEiwAnZb7lRmawmm1R33mhrN64G1avs1oA5JECeSUxLgBGYtdPHBSgMuEBg9ljRoCDbEQAvD_BwE&gclsrc=aw.ds

One downstairs in sink is a ceramic quarter turn and cold drips a little bit sometimes and I could not remove the sleeve and will ask a plumber to look at that as well

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What srcew mechanism you referring to, please?