Andehh Posted August 25 Share Posted August 25 We have been in the house for about a year now. Brick & block, block & beam bungalow. Due to irrational fears I turn the stopcock off when we go on Holiday. Our plumber also left us a pressure gauge on the main incoming feed after stop cock. We went away a few weeks ago, and I did my routine of turning off the stop cock...and came home to house with no pressure. I am 99% sure previous holidays (many months ago) never showed this level of pressure drop, maybe a slight one which I put down to change in temps or slowest of dripping taps. Over the last few weeks I have been going mad trying to figure out where we are loosing pressure. We seem to be dropping 0.1 per 30-60mins ish? 2.5 bar over night. We have no visible leaks anywhere, and I have used a damp meter to poke around everywhere inc through the carpets, through render, grout lines - all to nout. I am pretty sure I know where 90% of the pipe joints are in the ceiling (john guest) and there is no sign of anything damp. The drains show no trickle of water going through them, checked them all. We have no dripping taps anywhere. We have a water softener, but it isnt passing water through/no leaks near it. The pressure loss is on the water softener side of the house (so toilets, kitchen tap, utility tap and outside taps - all fine) I am really struggling with ideas now...all I can do is disable the water softener loop & the pressure holds fine. Pic below of the complicated , very sensible, plumbing layout. Disable individual zones seems to sometimes show a potential 'starting point' of leak on a section...but then retesting it later gives mixed results. Any technical people that could advise if any of our appliance connected to the Water Softener side of the water- ASHP, Pressure Vessels, washing machine, dish washer, etc could consistently, but unpredictable, influence the mains pressure after our stop cock? I'm all out of ideas Link to comment Share on other sites More sharing options...
Andehh Posted August 25 Author Share Posted August 25 Few pics here.... Link to comment Share on other sites More sharing options...
JohnMo Posted August 25 Share Posted August 25 That looks a complex system. What system is loosing pressure The main water The heating system or the unvented cylinder? Link to comment Share on other sites More sharing options...
Andehh Posted August 25 Author Share Posted August 25 (edited) Mains water. Master stop cock is out of picture, but as the water comes down it goes via the pressure valve and diverts, one to untreated cold water to house (no leak) other one to the water softener (leak). Every room has its own isolation valves, which should make it simple to identify which room... But the readings have been indecisive so far. Turns out it's hard work isolating the water to the house and rooms with 5 people in the house!! Edited August 25 by Andehh Link to comment Share on other sites More sharing options...
Dave Jones Posted August 25 Share Posted August 25 what happens if you just leave it alone. Link to comment Share on other sites More sharing options...
Temp Posted August 25 Share Posted August 25 Water isn't compressible so any pressure you have in the system with the stopcock is off is effectively maintained by stretch in the pipework which isn't much. In short you don't have to loose much water to loose pressure, especially if there is no expansion vessel. It could be as little as a dripping tap or WC. Temperature changes will also affect the pressure when off. Link to comment Share on other sites More sharing options...
JohnMo Posted August 25 Share Posted August 25 Check the unvented cylinder. There is an expansion vessel for that. If it has lost pressure that may cause the issue. Link to comment Share on other sites More sharing options...
Temp Posted August 25 Share Posted August 25 Just now, JohnMo said: Check the unvented cylinder. There is an expansion vessel for that. If it has lost pressure that may cause the issue. Isnt that part of a system normally isolated from the cold main? Link to comment Share on other sites More sharing options...
JohnMo Posted August 25 Share Posted August 25 1 minute ago, Temp said: Isnt that part of a system normally isolated from the cold main? Not really. The cold main is connected to the inlet group of the UVC, which is connected to the bottom port of the cylinder. The expansion vessel is connected either to the inlet group or cylinder contents via a port. So a closed main valve. A collapsed or punctured membrane on the expansion will alter system volume/pressure very easily. So worth checking. Also check the tundish at the UVC for drips. Good sign something is not right in that area could be a passing valve? 1 Link to comment Share on other sites More sharing options...
Alan Ambrose Posted August 25 Share Posted August 25 Bit of grit in one of the toilet valves maybe, giving the tiniest of all leaks? Should be abe to figure out by selectively shutting stuff off, say overnight. Or open up the cistern and observe any dripping? Link to comment Share on other sites More sharing options...
Conor Posted August 25 Share Posted August 25 Do you have a water meter? Take a reading next time before you go away for a day or two. 1 Link to comment Share on other sites More sharing options...
Andehh Posted August 26 Author Share Posted August 26 (edited) 13 hours ago, Dave Jones said: what happens if you just leave it alone. House & everything operates as normal, we have lived with this 'condition' for a few weeks now, without leak being visible. If I leave it alone - stop cocks open, all valves open..... all is well, and the pressure 'loss'' is topped up by mains incoming I guess, but technically we loose 0.1bar an hour 13 hours ago, Temp said: Water isn't compressible so any pressure you have in the system with the stopcock is off is effectively maintained by stretch in the pipework which isn't much. In short you don't have to loose much water to loose pressure, especially if there is no expansion vessel. It could be as little as a dripping tap or WC. Temperature changes will also affect the pressure when off. Yes, seems the total water loss is a 1/2 a cup per 24 hours I guess, but over a few weeks that does add up to bucket of water mysteriously disappearing.... 12 hours ago, JohnMo said: Check the unvented cylinder. There is an expansion vessel for that. If it has lost pressure that may cause the issue. We have two expansion vessels below, pictures below? 12 hours ago, Alan Ambrose said: Bit of grit in one of the toilet valves maybe, giving the tiniest of all leaks? Should be able to figure out by selectively shutting stuff off, say overnight. Or open up the cistern and observe any dripping? The toilets are plumbed into the 'non softened' side of the water works...which holds pressure fine! 12 hours ago, Conor said: Do you have a water meter? Take a reading next time before you go away for a day or two. No water meter. 12 hours ago, JohnMo said: Not really. The cold main is connected to the inlet group of the UVC, which is connected to the bottom port of the cylinder. The expansion vessel is connected either to the inlet group or cylinder contents via a port. So a closed main valve. A collapsed or punctured membrane on the expansion will alter system volume/pressure very easily. So worth checking. Also check the tundish at the UVC for drips. Good sign something is not right in that area could be a passing valve? Nothing via the tundish, even slid a bit of paper in to see if any drips. --------- Over night I turned off everything, all room valves hot & cold just as something I hadn't tried, pressure held fine (because stop cock --> Pressure gauge --> water softener --> several valves turned off). The next thing I opened up was the softened water feed to the heating systems (ie run a hot tap, this back fills the tank) and the pressure dropped to 1.5bar?? This makes me feel that something around the cylinder area lost some water - but with the valves closed leaving it to the taps, that its not them. I will try testing this again when we go out this afternoon. All departing hot valves closed, so stopcock --> Pressure valve --> Water softener --> DHW tank system --> hot valves closed). If there is indeed a leak in & around cylinder this would show with the Pressure valve dropping I think. We do have a very slight drip from one coupling on the ASHP closed loop, with the glycol in it, few drips a day & about 1 bar loss every other month. Small blue stain where the water evaporates off the floor. Seeing as this is a sealed loop, which I need to open 2 valves to top up every other months I presume its nothing to do with my mains water leak? Edited August 26 by Andehh Link to comment Share on other sites More sharing options...
Andehh Posted August 26 Author Share Posted August 26 (edited) Have a red one and a white one, pressure vessels ! The red one connects via the copper pipe below the immersion switch, and I presume is pressure for the heating circuit.... Where it's plumbed into the ASHP pipework. Not sure where the white one connects, can't follow the pipe behind the cylinder? Edited August 26 by Andehh Link to comment Share on other sites More sharing options...
JohnMo Posted August 26 Share Posted August 26 The white one is for the cylinder. When was the last time your cylinder was serviced? You need to be competent to work on unvented systems and they should be services annually. Link to comment Share on other sites More sharing options...
Andehh Posted August 26 Author Share Posted August 26 Probably when it was installed 12 months ago! Last resort is ringing out the existing plumber, but he is over 45mins away, and funds are so tight I'd like to try and rule out everything first. Link to comment Share on other sites More sharing options...
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