****ing boiler system...

[Bingy man]

I’d also say if the water company do confirm high pressure ask them what it is in bar . All taps and valves and boilers and water heaters are designed to operate within set parameters and won’t work correctly if they are outside these parameters. Low pressure is difficult because water companies have to supply water between ( I think) 1 and 2.5 bar and as long as they are reasonably close then they probably won’t go any further. High pressure is simple - fit a pressure regulator on the cold water supply and unless the pressure is extremely high the stop tap would normally be fully open and then closed 1/4 turn to help prevent it sticking. I’m wondering if your on a lead supply hence the stop tap being repaired and not completely replaced.

 

[Agent_zed]

Pressure and flow, whilst related, are 2 different things.

The stopcock can reduce flow but I don't believe it will reduce pressure. So if the house has 1 bar of water pressure to an open stopcock then there will be 1 bar of pressure on the other side (eg the house pipework) assuming all the taps are off.

If you turn the stopcock half off, there will still be 1 bar of pressure both sides. The pressure has to equalise and there is nothing in the stopcock preventing that equalisation. The flow will be reduced when you open the taps but the pressure will return to 1 bar when the taps are shut.

So opening the stoptap fully should have no difference in pressure whatsoever. You will get more flow but no difference in the system pressure.

 

[Cozzer]

Hmmm...OK.

Time to be a little more descriptive maybe.
I don't know whether the two problems - i.e. the F22 boiler errors, and the rattling pipes issue - were/are one and the same issue.
The boiler F22 problem seems to have been allayed for the time being. Haven't had an error since the magic stop leak stuff was added.

The rattling pipes issue...
1) Only ever affected upstairs. Nothing downstairs, shower/toliet/kitchen sink was affected. That's the location of the stop tap.
2) The bath/shower/toilet/wash basin upstairs - the location of the boiler - were affected by the horrendous rattling.
Example : wash hands in the sink? Get ready! It spat, groaned, pipes rattled so much you could literally feel it shaking the pedestal. For how long? As long as you had the tap running.
However, flush the toilet first, let the cistern start filling, and only then wash your hands....no trouble. No rattling, no vibration.

Ditto with the bath taps. As long as you flushed the toilet beforehand, no problem. The shower didn't seem to be affected in the same way, but then stopped working. Cold water OK, but hot never heated.

Back downstairs, we couldn't shift the stop tap, hence the plumber changing it. Once fitted, he closed it, using the kitchen sink to prove it. When closed, it's at 5 past the hour.
Turning it back to 12 noon (as it were) we had running water. Just, but running.
Open it to (say) 5 to the hour, we get an increased flow. Slower than we were used to, but running.
Nip upstairs, try the basin sink tap.....banging, spitting.
Turn basin tap off. Flush toilet, turn tap on.....it was fine. No noise, no vibration.
Back downstairs, turn stop tap to (maybe) 3 minutes to noon.
Back upstairs, run tap. Fine. No need to flush the toilet.
Ergo, we've left the stop tap at that setting...

There are suggestions above that I should open the stop tap fully. Frankly, I wouldn't dare. I've no idea what would happen....

 

[Jester129]

What did your neighbour say when you asked him about his water pressure?

 

[Sheptonphil]

...

There are suggestions above that I should open the stop tap fully. Frankly, I wouldn't dare. I've no idea what would happen....

there won’t be anymore pressure, the pressure is what it is as soon as you let any water through, just a more consistent flow for the volume that wants to pass the stop tap.
Opening the stop cock fully can’t generate more pressure but will decrease it (when any tap opened).

Rules of physics come into play Remember the formula PxV/ T= constant
Pressure x volume divided by Temp= constant
If you increase one, something els will drop to balance equation.
Increase flow (volume) then either temp or pressure will fall. As temp is what it is, then pressure (at opening flow) will fall. Just try it, there will be no pressure increase, quite the opposite.

It’s also why 22mm pipe is used on a gravity system, as there is less pressure, larger pipe is used to increase flow. Put that same feed reduced into 15mm pipe, the output pressure increases, but flow reduces. Think also garden tap off 4” mains, high pressure, but not much flow (comparatively) put it through a pressure washer, much higher pressure, even less flow. Pure physics.

 

[Spectric]

The stopcock can reduce flow but I don't believe it will reduce pressure.

You are correct @Agent_zed and controling the flow with the stop cock is not what it is there for. The way to resolve any problem requires a logical approach and the supplied pressure is the starting point in this situation, it has a direct bearing on everything downstream so you need to know what the supply pressure is before looking at the rest of the system but I would suggest it is within limits otherwise the water company would be getting more complaints, low pressure is the more common problem.

There are suggestions above that I should open the stop tap fully. Frankly, I wouldn't dare. I've no idea what would happen

Well with no taps open then nothing can happen, there would be no flow and no change in pressure. Only when you open a tap would you see a possible increase in flow due to the stop cock not restricting flow.

Example : wash hands in the sink? Get ready! It spat, groaned, pipes rattled so much you could literally feel it shaking the pedestal. For how long? As long as you had the tap running.
However, flush the toilet first, let the cistern start filling, and only then wash your hands....no trouble. No rattling, no vibration.

I would say your boiler issue and pipe banging are independant, but water hammer is caused when water is suddenly stopped from flowing, washing machine solenoid valves are a good example when moving water comes to a sudden stop but in your case it is opening a tap. This suggest it is more likely to do with air in pipework, you open a tap and water flows but any air in the system would have been compressed by the water and now expands, flushing the toilet increases the total flow and stops the banging so this is where a pressure gauge would assist. With your stop cock restricting flow and a tap opened is the flow through the stop cock sufficient to meet the demand, ie enough to fill and pressurise the pipe work whilst flowing ? If not then you must have partially filled pipework.

 

[profchris]

How about this as an approach, dealing with the (I'm sure correct) information about pressure and also your deep fears of a watery apocalypse:

1. Flush toilet
2. Open one or more taps
3. Open stopcock fully. If the kitchen tap is open, you'd see if flow suddenly increased. The pressure information suggest you'll see more flow, but not scarily so.
4. Close taps in turn, finishing with kitchen tap - if hammer starts, reopen tap, return stopcock to previous position reassess.
5. If all taps close OK, reopen kitchen tap and see what happens.

 

[Agent_zed]

My guess to why the pipes bang in certain places and not others is that most likely they aren't as secured in those places. It may also be that the pressure waves are being dampened in certain places eg going through an isolation valve or flexible tap tails.

It's obviously entirely up to you what you do but for me I think after some thought I'd leave all the taps shut and slowly open the stop tap to full. There should be no pressure change and no flow so nothing should change. Then slowly open a tap a little and see if the banging starts. I wouldn't flush the toilet though as you won't have control to turn it off quickly if you need to.

I wouldn't be surprised if your banging went away once it's full open.

Or get a plumber in, as that's really the only other solution.

 

[Dave Moore]

Pressure is not determined by the amount the valve is open , only the volume(flow).
Dave

 

[Cozzer]

Right, chaps...
Borrowed the neighbour's phone again - didn't realise you could do videos on these things as well! Very clever!
Anyway, I chickened out a little - I opened the stoptap one whole revolution from closed and tried the bathroom hot tap....

Just a little 6" flavour of it. Not so sure it's evident on the video, but the basin was actually vibrating enough to cause the water to ripple....

Should have added that I then flushed the toilet, and turned the same tap....no noise, no vibration.
Suffice to say, the stop tap is back at 5 mins (approx) to closed!

 

[Cozzer]

Someone above mentioned Severn Trent... I looked on their site this afternoon, and noted one of their "Test your water flow" suggestions.
()
Given certain conditions, it should take 7 seconds to fill a 1 litre bottle.
With our stoptap at circa 5 to the hour - i.e. nearly closed - it took between 4 and 5 seconds.
The guide suggests what to do if your test takes longer than 7, but nothing if quicker!)

 

[Bingy man]

Right, chaps...
Borrowed the neighbour's phone again - didn't realise you could do videos on these things as well! Very clever!
Anyway, I chickened out a little - I opened the stoptap one whole revolution from closed and tried the bathroom hot tap....

View attachment 176406

Just a little 6" flavour of it. Not so sure it's evident on the video, but the basin was actually vibrating enough to cause the water to ripple....

Should have added that I then flushed the toilet, and turned the same tap....no noise, no vibration.
Suffice to say, the stop tap is back at 5 mins (approx) to closed!

That is 100% water hammer - re read my post above . It will shake the house all through and beyond. You may have to replace the taps or the valve side - available but in several sizes.
Tracing the actual tap is not always easy . Edit Bath and basin taps both suspects and so are the kitchen taps -.do you have isolating valves fitted on the pipes ? If yes then turn them off and try the stop tap again ..

 

[Silfi]

If you have a wahing machine connection with an isolating valve attaching a pressure gauge like this--
https://ffx.co.uk/products/silverli...6146?msclkid=21d7b586f44e121b9244d05143050c5f
would determine the mains pressure.

 

[Cozzer]

That is 100% water hammer - re read my post above . It will shake the house all through and beyond. You may have to replace the taps or the valve side - available but in several sizes.
Tracing the actual tap is not always easy . Edit Bath and basin taps both suspects and so are the kitchen taps -.do you have isolating valves fitted on the pipes ? If yes then turn them off and try the stop tap again ..

Interesting. The kitchen sink taps - a fancyarsed thing, 2 taps, 1 outlet - and the bathroom sink taps (Bristan?) were fitted at the same time...a couple of years ago.
As for isolating valves...I wouldn't know one if it hit me in the April...

 

[Cozzer]

What did your neighbour say when you asked him about his water pressure?

Not much.
Along the lines of "turn tap on, and there it is..."

More concerned about me borrowing his phone, I think.

 

[Spectric]

I have recalled that some time back when I built our new bathroom we had something similar to yourself, but it was only the cold tap on the bath that caused pipe noises and the noise stoped when the sink cold tap was opened. The bathtaps were these from burlington and are screw down not ceramic cartridge. The pipes were 22mm and fully clipped so I knew loose pipes was not the issue. I did not solve the actual problem but fitted an expansion vessel where the pipe drops down from above, only place to fit one.

 

[Bingy man]

Interesting. The kitchen sink taps - a fancyarsed thing, 2 taps, 1 outlet - and the bathroom sink taps (Bristan?) were fitted at the same time...a couple of years ago.
As for isolating valves...I wouldn't know one if it hit me in the April...

They come in many guises but are similar to these , it just means you can isolate that particular tap or taps from your supply to if nothing else eliminate it..

 

[Spectric]

On the subject of isolating valves do not buy the cheap ones as they can seep after a while, I always use the ones from Peggler and never had any issues.

 

[Bingy man]

They were just to show the op what they were, agree regarding the cheap ones and they also restrict the flow severely.

 

[Cozzer]

Back to F22 this morning.


Not the only F used....