Water Supply 'Tripping'

[MrGatch]

Really odd problem with my cold water supply stopping abruptly with flow suddenly halting with a water hammer.

I've been doing loads of work on upstairs bathroom and have been switching the water off and on a number of times over the last month to plumb in new toilet, sinks, shower, bath etc. The new pipework has been extensive - its not a straightforward swap-out.

I switched the water back on at the stopcock most recently (with a tap running) and the supply just seem to shut down. The only way I could get it to come back was to switch the stopcock off completely and then very slowly turn it back on. Too fast and it would shutdown again.

The setup is all in 22mm copper: stopcock > Water Meter (new 32mm model) > Check Valve > PRV (part of a OSO Super S) > Taps

Any ideas? It feels like the meter but I think that's unlikely. Faulty check vale or stopcock? The switch-off is really abrupt.

Thanks!

 

[townfanjon]

Switch !! the stopcock ? if its one of those surestop switches I would bin it and put a proper one on or a good quality lever arm .

 

[snowhead]

A few things,

You mention OSO, is this an unvented that you are fitting?

Firstly check the last alteration you made before the trouble started
Also try splitting the system up to check flow progressivley from the source.

 

[gpbeck]

I had this problem with a faulty water meter.

 

[Last Plumber]

Is the stop tap (or any other stop tap in that run) installed with the correct orientation?
If water flows the wrong way through a stop tap (particularly an old one with a loose jumper) they will slam shut once water flows through them fast enough.

 

[centralheatking]

Really odd problem with my cold water supply stopping abruptly with flow suddenly halting with a water hammer.

I've been doing loads of work on upstairs bathroom and have been switching the water off and on a number of times over the last month to plumb in new toilet, sinks, shower, bath etc. The new pipework has been extensive - its not a straightforward swap-out.

I switched the water back on at the stopcock most recently (with a tap running) and the supply just seem to shut down. The only way I could get it to come back was to switch the stopcock off completely and then very slowly turn it back on. Too fast and it would shutdown again.

The setup is all in 22mm copper: stopcock > Water Meter (new 32mm model) > Check Valve > PRV (part of a OSO Super S) > Taps

Any ideas? It feels like the meter but I think that's unlikely. Faulty check vale or stopcock? The switch-off is really abrupt.

Thanks!

The best way to establish the cause of your problem is ...I assuming you failed to test at each new stage...is to take out or bypass each of the units that can cause the shutdown in turn and see what happens. As usual go for the ‘dogey’ units first.. looking for the line of weakness first. Starting with the sure stop first ..they are really good units I have a few in my holiday lets but they are quite ‘hit and miss’ and as I did not design them have no idea why they do not always fulfill the designers promise.
Great solid company behind SureStop Centralheatking

 

[MrGatch]

Thanks for the replies.

Before I start dismantling things does you guys know if any of the components listed could cause this sort of fault?

Its a regular brass stopcock (this one), not a Surestart. Is this a possible fault with this sort of tap?

Can a check valve (this one) cause this sort of fault?

gpbeck - Did your water meeting have this exact fault?

Cheers!

 

[snowhead]

Is the PRV (regulating valve) in the source pipework to all the taps or just to the Hot side?
Either way is it both Hot and Cold affected?

 

[Last Plumber]

You will normally find a directional arrow on the side of a stop tap.

 

[MrGatch]

The PRV is is part of the cylinder and regulates the pressure on both the hot cold - the cold supply connects through it.

The stopcock is the right way round.

 

[gpbeck]

Thanks for the replies.

Before I start dismantling things does you guys know if any of the components listed could cause this sort of fault?

Its a regular brass stopcock (this one), not a Surestart. Is this a possible fault with this sort of tap?

Can a check valve (this one) cause this sort of fault?

gpbeck - Did your water meeting have this exact fault?

Cheers!

Problem was caused when plumber started work. No water hammer, just silent frustration. You need to check if there is water pressure before the meter when you have no flow. Slacken off a union or something.