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I’ve just had a thought is the red lever the mains into the cylinder cupboard and they’ve put the cylinder kit on the wrong pipe ?
Discuss Cold water flow problem has stumped 3 plumbers...can you help?! in the UK Plumbing Forum | Plumbing Advice area at PlumbersForums.net
I've just checked, no the mains is the blue switch/PRV pipe on the left.I’ve just had a thought is the red lever the mains into the cylinder cupboard and they’ve put the cylinder kit on the wrong pipe ?
Correct - water flows through into the showers. So either that pipe is also connected somehow to the mains or it's water flowing back from the cylinder into the pipe with the red lever? It's running through cold for the minute or so I tried it, but presumably if it's the water at the bottom of the tank it's likely to be cold as the boiler won't have been on to heat what has been re-filled.But you have mains water coming through back on the red one eg turn the blue one off and open a shower and you still have cold only ?
Seems to be a form of block valve but not a ERV, lifts at 8bar ("mains") but incorporates a NRV. (no bearing on current problems).Is the "RWC 8, 4 bar" (far right) a PRV (pressure reducing valve) and if so, why apparently a waste pipe off it?, or is it a ERV (expansion relief valve) but connected at both ends???.
Our understanding is yes, it does rise to the top before heading back down.I know I asked this before but there was no reply.
Does the cold rise to the top floor then feed the lower floors?
What is the mains pressure at the ground level?
I know it might seem a silly question but to my mind, this is getting too complicated. You need to rule out the simple things first.
This is what we know so far. As yet, we've not been able to work out which line feeds the rest of house: I.E Kitchen, cold in bath, bathroom sink and toilet, ground floor bathroom sink and toilet and outside tap.Be handy now that all have lever valves to label them individually and text briefly explaining what floor etc they are supplying.
If all flows reduce proportionally then points to pressure issue, can't understand why a pressure gauge seems to be a rarity on most unvented systems which depend solely on mains pressure, the PG can tell such a lot.This is what we know so far. As yet, we've not been able to work out which line feeds the rest of house: I.E Kitchen, cold in bath, bathroom sink and toilet, ground floor bathroom sink and toilet and outside tap.
Thanks - yes this is what my plumber thinks os the issue - the problem is that we've replaced/removed all the 'visible' NRV on the system (as pictured) and still the problem remains.This erratic behaviour could be explained by faulty/sticking non-return valves, quite possibly fitted the wrong way around.
These have plastic parts inside and operate against a spring, I’ve had damaged ones where the ‘mechanism’ gets jammed sideways and moves around a bit. Ended up with a hand full of bits we I removed it all. Replaced with a new one and problem solved.
Should be a single check valve on the incoming MCWS feed to the cylinder to prevent possible HWS backflow only. Not sure why you have another single and a double check on the other bit pipework there, will be a flow restriction. I would also relocate the PRV closer to the inlet pipe feeding in to the cylinder only as you are restricting the whole system in its current position.
Yes! I put a note in every neighbours house - 2 came back to me.Any neighbours with the same house? If so, any had problems?
Thanks for this - I think before anymore exploratory work i'll ask them to do exactly this next.From the updated pictures this is still relevant and hasn't been ruled out yet to my knowledge. Relocate the PRV to the correct position, install a single check valve in the correct position on the cylinder inlet and remove the other multiple check valves not required. The PRV in its current position is restricting the overall system and with the multiple NRVs not needed as well as being installed in sequence the flow is being further restricted.
The water pressure is a consideration - although as mentioned before none of the technicians felt it was an issue - I don't have the necessary tool, nor a suitable plug to fit it on (outside tap is one effected by this low/no flow).Yes, this has a check valve but even if faulty or the valve has been installed wrong way round, the cylinder will still be supplied from the shower supply (which in shouldn't), just shutting that red lever valve will prevent this and also prove that the cylinder is being correctly supplied.
Personally, before doing anything more and in view of flows back to normal this morning, I wouldn't spend another cent but I would go away and invest in a £10 pressure gauge that you yourself can screw on to your outside tap and observe it for a few hours or so, its so simple and basic to do this IMO.
10LPM isn't a bad flow from shower cold only, you could just measure flow rate with shower at its normal temperature setting and while this will be the sum of hot+cold flowrates, it still reflects the total mains cold water flowrate. If this is normal, say, 12/15LPM and if the downstairs flowrate is still very poor immediately after completing this test then it would appear to be a internal problem.The water pressure is a consideration - although as mentioned before none of the technicians felt it was an issue - I don't have the necessary tool, nor a suitable plug to fit it on (outside tap is one effected by this low/no flow).
My bathroom taps have built in aerator things - so I tried the bit rudimentary method of taking the hose of the shower mixer tap, and filling a jug of water on just the cold setting - it blasted out well over a litre in 6 seconds. Although I don't know if that how accurate that test would be if through the mixer there is some cylinder water pressure, even turned to full cold?
I would suggest you buy a pressure gauge and take the pressure.Our understanding is yes, it does rise to the top before heading back down.
I don't know what the mains pressure is, but one of the first things we did was get welsh water in and they checked it and said the flow was good into the house.
As far as I know the pressure is OK, none of the other technicians have been concerned about it, it seems adequate enough to flow well on the top floor and fill the cylinder as normal.
HOWEVER - the plot thickened this morning - I woke up and went to the kitchen and for the first time in 5 weeks the cold taps were suddenly running at 80/90% power. I left them running for 4/5 mins, no stop in flow. I went the the bathroom next door, the taps worked. I left the tap running and flushed the toilet, the tap slowed to about 30/40% but kept going.
I had to pop out and when I came back, it was still working at this slightly reduced level. So I went around and checked everything that hadn't worked and it was working. 30 mins later, it's all stopped again.....
So this slightly dispels the blockage theory and seems much more a pressure issue, right? I suppose there could still be a faulty PRV somewhere behind a wall, but it seems unlikely it would just randomly start working again?
Reply to Cold water flow problem has stumped 3 plumbers...can you help?! in the UK Plumbing Forum | Plumbing Advice area at PlumbersForums.net
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