Jenni Posted October 5, 2020 Share Posted October 5, 2020 Hello. Picture is a diagram of what I think my water pipe layout needs to be. I'd really appreciate some advice on what size (plastic) pipe to use please? Most urgently for the 2 long runs to the UVC and Bath etc, as I need to run these through ducts ASAP. Link to comment Share on other sites More sharing options...
tonyshouse Posted October 5, 2020 Share Posted October 5, 2020 All 15mm with reasonable mains pressure do you have a cold cistern in the loft? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 5, 2020 Share Posted October 5, 2020 OK. Why is there a bathroom on hard and a bathroom / other stuff on soft? Why the pressure valve? I assume you mean PRedV ( pressure reducing valve ). One will come with, and need to be fitted to the UVC. That valve ( serviced by soft water ) will have a balanced cold outlet for soft feeds to all mixer taps, so would need to go to a soft cold manifold fed from the 'control group' at the UVC. The UVC must NOT be serviced after all the other cold feeds. It must have "cold mains priority" which means 22mm pipe feed from the cold mains direct to the UVC WITHOUT anything drawing off in between ( in an ideal world ). If this is being done from scratch then I would observe this discipline religiously. Outside taps should be outside off the rising cold mains, but if they have to be T'd off internally and taken through external walls then they need to be T'd in AFTER the stopcock, but BEFOFRE the 1st PRedV without exception. The above drawing needs to be scrapped sorry, loads of faux pas there. Ask questions, we'll answer them 1 Link to comment Share on other sites More sharing options...
Jenni Posted October 6, 2020 Author Share Posted October 6, 2020 21 hours ago, tonyshouse said: All 15mm with reasonable mains pressure do you have a cold cistern in the loft? There isn't any loft, single storey barn conversion. All mains pressure with an unvented cylinder. (When I filled the UFH manifold with a hosepipe, the guage on there got to about 3 bar). 20 hours ago, Nickfromwales said: OK. Why is there a bathroom on hard and a bathroom / other stuff on soft? Why the pressure valve? I assume you mean PRedV ( pressure reducing valve ). One will come with, and need to be fitted to the UVC. That valve ( serviced by soft water ) will have a balanced cold outlet for soft feeds to all mixer taps, so would need to go to a soft cold manifold fed from the 'control group' at the UVC. The UVC must NOT be serviced after all the other cold feeds. It must have "cold mains priority" which means 22mm pipe feed from the cold mains direct to the UVC WITHOUT anything drawing off in between ( in an ideal world ). If this is being done from scratch then I would observe this discipline religiously. Outside taps should be outside off the rising cold mains, but if they have to be T'd off internally and taken through external walls then they need to be T'd in AFTER the stopcock, but BEFOFRE the 1st PRedV without exception. The above drawing needs to be scrapped sorry, loads of faux pas there. Ask questions, we'll answer them I don't really like the feel of softened water, but I recognise the benefits of it to appliances, toilet flushes and UVC in particular. The pressure valve due to some previous damaged caused by water co allowing pressure to go too high in the past, just trying to mitigate risk. I've tried to do the diagram to also show the relative positions of things. As a barn conversion there have been various compromises, the water comes in a one end where the kitchen and utility are nearby, then the bathroom plant room is well over the other side. I understand what you're saying about the UVC having cold mains priority, but I'm not sure how to achieve this while also having hard water to cold taps within the physical constraints. No problem moving the outside taps to just after the stopcock, I am interested to know the logic behind this please? Thank you. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 6, 2020 Share Posted October 6, 2020 1 hour ago, Jenni said: No problem moving the outside taps to just after the stopcock, I am interested to know the logic behind this please? Taking the O/S taps off straight after the stopcock and before the primary PRedV will preserve the premium flow rates and will then make that available mains potential divisible between the house and the O/S taps. Best practice is to have them off the rising cold mains, BEFORE it even enters the house. Stealing that further downstream would have a much bigger impact on the flow available at the nearest outlets to where you’ve T’d off. 1 hour ago, Jenni said: The pressure valve due to some previous damaged caused by water co allowing pressure to go too high in the past, just trying to mitigate risk. Damn good idea. I’ve seen some folks mains peaking out at over 11 bar and things blowing up / off with catastrophic consequences. Set that to 4 bar, and then make sure the secondary one is STILL fitted at the UVC. The difference between them, the UVC one ( aka control group ) will be factory set at 3 bar, will need to be mitigated. You’ll need a single check NRV on the 22mm hot outlet of the UVC to stop back pressurisation of the UVC from the mixer taps / shower mixers etc. 1 hour ago, Jenni said: I understand what you're saying about the UVC having cold mains priority, but I'm not sure how to achieve this while also having hard water to cold taps within the physical constraints. That is your cross to bear I’m afraid. I can only advise as to what you ‘should’ be doing, you can achieve what you can Are you trying to do as little disturbing of the property as possible? Tough nut to crack if so. 1 hour ago, Jenni said: Thank you. You’re welcome ! Link to comment Share on other sites More sharing options...
tonyshouse Posted October 6, 2020 Share Posted October 6, 2020 Need to distinguish between pressure and flow, they are different Link to comment Share on other sites More sharing options...
Jenni Posted October 7, 2020 Author Share Posted October 7, 2020 Trying to take on board your advice Nick, here's version 2. I've jotted on approx distances in meters, and potential pipe diameters in millimetres. Any better? Link to comment Share on other sites More sharing options...
Jenni Posted October 15, 2020 Author Share Posted October 15, 2020 Hi @Nickfromwales, do you think my second attempt is an improvement on the first? Any further suggestions please? I'm keen to nail down the basic setup so I can install the main pipework into ducts shortly. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 15, 2020 Share Posted October 15, 2020 1 hour ago, Jenni said: Hi @Nickfromwales, do you think my second attempt is an improvement on the first? Any further suggestions please? I'm keen to nail down the basic setup so I can install the main pipework into ducts shortly. Will have a butchers later ? Link to comment Share on other sites More sharing options...
Jenni Posted October 27, 2020 Author Share Posted October 27, 2020 Hi @Nickfromwales, any chance you've got a chance to check out revised drawing please? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 27, 2020 Share Posted October 27, 2020 3 minutes ago, Jenni said: Hi @Nickfromwales, any chance you've got a chance to check out revised drawing please? Oops. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 27, 2020 Share Posted October 27, 2020 I’ll put a man on it shortly. ?? 1 Link to comment Share on other sites More sharing options...
Crofter Posted October 27, 2020 Share Posted October 27, 2020 Apologies if this hijacks the thread... I'm about to swap out a plain vanilla vented direct cylinder for its unvented cousin. I'd assumed that I could just plumb it in as-was. But reading through this thread, I realise that it's not as simple as that! Current setup is 22mm from stopcock at kitchen sink, heading off to the bathroom. The first tee is a 15mm to the kitchen (sink, dw, outside tap), the next tee is a 15mm to the existing cylinder, and then the bathroom is at the end. If I need to give the tank priority, that means a big loop up there straight after the stopcock, and then back down again. Or put the tank somewhere else. Not a deal-breaker, just something to think about. Glad I spotted this! I'm planning on getting a plumber to do the essential hookup of the UVC itself but wanted to do all the prep myself, so I'm sure he would have picked me up on this. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 28, 2020 Share Posted October 28, 2020 3 hours ago, Crofter said: Apologies if this hijacks the thread... I'm about to swap out a plain vanilla vented direct cylinder for its unvented cousin. I'd assumed that I could just plumb it in as-was. But reading through this thread, I realise that it's not as simple as that! Current setup is 22mm from stopcock at kitchen sink, heading off to the bathroom. The first tee is a 15mm to the kitchen (sink, dw, outside tap), the next tee is a 15mm to the existing cylinder, and then the bathroom is at the end. If I need to give the tank priority, that means a big loop up there straight after the stopcock, and then back down again. Or put the tank somewhere else. Not a deal-breaker, just something to think about. Glad I spotted this! I'm planning on getting a plumber to do the essential hookup of the UVC itself but wanted to do all the prep myself, so I'm sure he would have picked me up on this. What is the cold mains pressure / flow like? I've done plenty of UVC installs where there is only a 15mm cold feed to tap into, and they worked fine. You just need to understand that if you have multiple cold devices running when you want a shower, it'll be a less-than-amazing shower. That's all 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 28, 2020 Share Posted October 28, 2020 4 hours ago, Jenni said: Hi @Nickfromwales, any chance you've got a chance to check out revised drawing please? OK, I've had a loom and all seems good to go. There should be a double-check NRV immediately after the stopcock, and then a drain off cock. Make sure the outside taps have NRV's in them. Do you need the second hard manifold? Ideally you'd make the 1st hard manifold bigger and run the 3x bathroom hard feeds back to that. No issue with your setup as is, if that is easier. "Carry on!" Link to comment Share on other sites More sharing options...
Jenni Posted October 29, 2020 Author Share Posted October 29, 2020 On 28/10/2020 at 00:15, Nickfromwales said: OK, I've had a loom and all seems good to go. There should be a double-check NRV immediately after the stopcock, and then a drain off cock. Make sure the outside taps have NRV's in them. Do you need the second hard manifold? Ideally you'd make the 1st hard manifold bigger and run the 3x bathroom hard feeds back to that. No issue with your setup as is, if that is easier. "Carry on!" NRVs and drain off, points noted ? The second hard manifold is debatable I suppose. I have a 50mm duct to run through. I thought a single larger bore pipe that splits to smaller near point of use might be easier than trying to get 2x 15mm and a 10mm pipe down the 50mm duct. I suppose I could go with just 2x 15mm and T off a 10mm for the basin (from the bath 15mm)? I've read that 15mm is recommended for high demand items like bath+shower. And that WCs and hand basins are fine/better with 10mm. But I'm not sure about appliances like dishwasher and washing machine - is there a minimum size they need? Last thing, any pointers on what size pipe I should use from the softener to the UVC? And size pipe to the 2 (possibly 3) manifolds? Thank you ? 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 29, 2020 Share Posted October 29, 2020 5 minutes ago, Jenni said: NRVs and drain off, points noted ? The second hard manifold is debatable I suppose. I have a 50mm duct to run through. I thought a single larger bore pipe that splits to smaller near point of use might be easier than trying to get 2x 15mm and a 10mm pipe down the 50mm duct. I suppose I could go with just 2x 15mm and T off a 10mm for the basin (from the bath 15mm)? Stick with whatever is easiest tbh. It's not worth losing sleep over 6 minutes ago, Jenni said: I've read that 15mm is recommended for high demand items like bath+shower. And that WCs and hand basins are fine/better with 10mm. But I'm not sure about appliances like dishwasher and washing machine - is there a minimum size they need? 15mm always to showers / baths, and 10mm to basins. WC's remain a bone of contention because some take an excessively long time to fill back up on 10mm feed. Geberit etc makes no odd's as the tiny flexi inside the cistern s about 6mm or 8mm so restrictions are present there anyhoo..... 8 minutes ago, Jenni said: Last thing, any pointers on what size pipe I should use from the softener to the UVC? And size pipe to the 2 (possibly 3) manifolds? All 22mm. 9 minutes ago, Jenni said: Thank you ? ? 1 1 Link to comment Share on other sites More sharing options...
Jenni Posted October 30, 2020 Author Share Posted October 30, 2020 That's great. Thank you for your advice Nick ? Link to comment Share on other sites More sharing options...
Nick Laslett Posted October 19, 2022 Share Posted October 19, 2022 On 29/10/2020 at 20:38, Jenni said: The second hard manifold is debatable I suppose. I have a 50mm duct to run through. I thought a single larger bore pipe that splits to smaller near point of use might be easier than trying to get 2x 15mm and a 10mm pipe down the 50mm duct. I suppose I could go with just 2x 15mm and T off a 10mm for the basin (from the bath 15mm)? Hello @Jenni, what did you do in the end? 1 larger pipe in 50mm duct to satellite manifold, or multiple smaller pipes down 50mm duct? I’m thinking of putting 2x15mm, 1x10mm down a 50mm duct to supply bath, shower & basin. Link to comment Share on other sites More sharing options...
Jenni Posted October 19, 2022 Author Share Posted October 19, 2022 Hi @Nick Laslett, I went with a single 22mm in the 50mm duct. All seems to be working well so far, although I'm not complete / fully functioning in general yet. Link to comment Share on other sites More sharing options...
Nick Laslett Posted March 7, 2023 Share Posted March 7, 2023 Just getting back to some plumbing tasks. I have always liked this thread’s discussion about hot & cold design because it was so clear. Re-reading, I picked up on the point about “cold mains priority”, which I’ve not seen mentioned much in other threads. This led to @Jenni adding the Control group box to her schematic. A quick google led me to this very fancy looking valve. My question was do I need one of these to give my Sunamp cold mains priority? @DamonHD, @ToughButterCup, @Russdl do you guys have any thoughts on this question based on your installs? Midsummer Energy have this kind of valve as part of the Sunamp page, but the actual Sunamp manual is suitably vague. https://midsummerwholesale.co.uk/buy/sunamp-heat-batteries Link to comment Share on other sites More sharing options...
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