Miller3857 Posted June 18, 2018 Share Posted June 18, 2018 Hi first ever question so please be gentle, although I have been reading the forum for some time. Currently planning the plumbing for two ensuites (two of five). Both have showers and the pipe run from the thermal store to each is 17m, both ensuites back onto each other. I want to keep things as simple as possible but appreciate there needs to be a balance between simplicity and functionality. Naively I had hoped to feed each one back individually to the store and a manifold, interested to hear your views? Link to comment Share on other sites More sharing options...
ProDave Posted June 18, 2018 Share Posted June 18, 2018 17M is a long way. The issue is the time it takes the hot water to get to the tap. I would first look at getting the HW tank more central, if not a recurculating hot water system. Link to comment Share on other sites More sharing options...
PeterW Posted June 18, 2018 Share Posted June 18, 2018 17m at 15mm is 2.3 litres of water before you get hot at the shower, at 22mm its 5.3 litres. I would look at running 15mm for each of the showers from a manifold - 28mm off the tank to allow for multiple showers - and then run 10mm to the basins as thats less than a litre in 17m of pipe. How big is the TS and is it a coil or a plate heat exchanger..? Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 18, 2018 Share Posted June 18, 2018 If the pipe is going to the showers, then one assumes it'll also be going to the basins in those rooms too. The showers are inconsequential as you just open the tap at high flow and wait, no bother at all there, but the basin taps will likely hardly ever see hot water when washing your hands briefly after using the loo. Hot recirculation circuit system is a no-brainer here afaic. Sounds like a big house too so I'd run the HRC to all outlets to maximise the cost / benefit. Running a HRC is not very costly, and if no concern whatsoever if you have PV to offset your energy consumption. 7 minutes ago, PeterW said: I would look at running 15mm for each of the showers from a manifold - 28mm off the tank to allow for multiple showers - and then run 10mm to the basins as thats less than a litre in 17m of pipe. That's exactly what @jacks plumbers did with wait times of 45 seconds for hot water to basins. I'd do the same eg 28-22-15mm series pipework and leave the manifolds, but I'd run the HRC to each bathroom 22mm supply where it tees and dropscto 15mm and super insulate all the hot and HRC pipework. More info please @Miller3857 ! Link to comment Share on other sites More sharing options...
PeterW Posted June 18, 2018 Share Posted June 18, 2018 2 minutes ago, Nickfromwales said: I'd do the same eg 28-22-15mm series pipework and leave the manifolds, but I'd run the HRC to each bathroom 22mm supply where it tees and dropscto 15mm and super insulate all the hot and HRC pipework. For 5 ensuites...??? ? I'm assuming we are talking a 750 or 1000 litre TS here..? With a 60-70kw DHW coil or PHE..?? And all the joy of a TS with a HRC.... hmm.... flow switch and pump anyone..?? @newhome...? 1 Link to comment Share on other sites More sharing options...
jack Posted June 18, 2018 Share Posted June 18, 2018 13 minutes ago, Nickfromwales said: That's exactly what @jacks plumbers did with wait times of 45 seconds for hot water to basins. They somehow did worse than that. The shower in this bathroom takes 3 seconds to start warming up. The basin takes over 40 seconds. The downstairs plant room with UVC is just to the right of right hand wall: I assume the shower pipework goes straight up inside the wall, whereas the basin suffers from a much longer route. It's possible the longer route was required to get around, eg, drainage and MVHR runs. I'm just not sure. We should definitely have had HRC to our kitchen (~12m run from UVC) and downstairs toilet (~8m run). Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 18, 2018 Share Posted June 18, 2018 31 minutes ago, PeterW said: I'm assuming we are talking a 750 or 1000 litre TS here..? With a 60-70kw DHW coil or PH You design it according to the remit . Does the OP want :- ? To run 2, 3, or 4 or more showers simultaneously.... To size the entire system to the dwelling, or to their actual needs.... Does the OP have sufficient cold mains flow / pressure to support the above? Are accumulators to be involved if mains is insufficient? Has a thermal store been fitted yet? Why specify a TS when this may be better off with a large UVC or pair of medium sized UVC's? Lets see how the hot water is going to be pushed around the building before deciding what the hot water system can / cannot do. 1 Link to comment Share on other sites More sharing options...
newhome Posted June 18, 2018 Share Posted June 18, 2018 (edited) 51 minutes ago, PeterW said: And all the joy of a TS with a HRC.... hmm.... flow switch and pump anyone..?? @newhome...? I think the fact that I have no idea what you’re on about is probably a good thing at this point What’s an HRC? Edited June 18, 2018 by newhome 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 18, 2018 Share Posted June 18, 2018 What happens on tour stays on tour. Link to comment Share on other sites More sharing options...
newhome Posted June 18, 2018 Share Posted June 18, 2018 8 minutes ago, Nickfromwales said: What happens on tour stays on tour. Was that when @PeterW dressed up in my clothes when I was collecting that bloody flow switch from hundreds of miles away? Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 18, 2018 Share Posted June 18, 2018 And your shoes ? Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 18, 2018 Share Posted June 18, 2018 1 hour ago, newhome said: What’s an HRC Hot Return Circuit. The pump you have that ( when fitted correctly ) massively reduces the delay in getting hot water out of any outlet. 1 Link to comment Share on other sites More sharing options...
newhome Posted June 18, 2018 Share Posted June 18, 2018 1 minute ago, Nickfromwales said: Hot Return Circuit. The pump you have that ( when fitted correctly ) massively reduces the delay in getting hot water out of any outlet. Thanks! So I don't have one of them? Link to comment Share on other sites More sharing options...
PeterW Posted June 18, 2018 Share Posted June 18, 2018 Yep you’ve got one @newhome and the flow switch makes it work ..... worth the 7 hour drive eh..?? Link to comment Share on other sites More sharing options...
newhome Posted June 18, 2018 Share Posted June 18, 2018 1 minute ago, PeterW said: Yep you’ve got one @newhome and the flow switch makes it work ..... worth the 7 hour drive eh..?? Cool! Yeah, I've finished my time in rehab recovering from that day so all good now . Link to comment Share on other sites More sharing options...
newhome Posted June 18, 2018 Share Posted June 18, 2018 This thing then huh? Link to comment Share on other sites More sharing options...
PeterW Posted June 18, 2018 Share Posted June 18, 2018 Yup ... comes on when the TS pump comes on ... 1 Link to comment Share on other sites More sharing options...
Miller3857 Posted June 18, 2018 Author Share Posted June 18, 2018 Thank you for all the replies! Unfortunately I can't move the tank. The thermal store is a 750 litre Akvaterm fed from a 30kw wood burning stove (I can hear the groans) backed up by gas and 4kw of solar PV. We are looking to have a mains accumulator to allow for multiple shower use should the need arise. If I'm honest the thinking behind the hot water system has gone into the too difficult box until now. Link to comment Share on other sites More sharing options...
Miller3857 Posted June 20, 2018 Author Share Posted June 20, 2018 Ok, so a HRC is being suggested as the best solution. Having read previous threads my understanding is that the flow could be started by an occupancy detector in each bathroom, what happens when the 'ring main' gets up to temperature does the pump stop with a temperature switch or does it stay running? Does anyone have a diagram showing the relationship between the pump and the cold water supply going into the coil in the TS - is it best for the pump to be on the return leg or on the flow? Lots of questions and some may appear a little vague so apologies but just trying to get my head around things. Thank you. Link to comment Share on other sites More sharing options...
PeterW Posted June 20, 2018 Share Posted June 20, 2018 Pump goes onto the return leg with a non return valve in front of it to stop it back flowing to the taps. If you calculate the volume of the loop you can work out how long the pump needs to run for - surprised if it’s more than 20-30 seconds. Your other - neater - option is to use a flow switch in the cold main that senses flow. That could be a toilet being flushed or even a tap being turned on and then the pump runs for 20-30 seconds which is more than enough to clear any cool water. Benefit of this is you don’t need any wiring or sensors to trigger the pump and at worst it runs every time someone opens a cold tap which means the house is occupied ... Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 20, 2018 Share Posted June 20, 2018 If the flow switch is on the cold directly before the TS DHW coil then it will only trigger when a hot tap is open, which would be my suggestion. Motion sensors will trigger the HRC pump even if you go in just to empty the linen basket Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 20, 2018 Share Posted June 20, 2018 On 18/06/2018 at 17:37, PeterW said: Yup ... comes on when the TS pump comes on ... ( whispers gently ) it's the green pump, behind that one Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 20, 2018 Share Posted June 20, 2018 On 18/06/2018 at 17:20, newhome said: Thanks! So I don't have one of them? You do, but I doubt that whomever plumbed the system ran the HRC return pipework all the way to each basin so, although the system works, it's not reducing the delay for hot water as effectively as it could be. Better than nowt though, and you'd soon notice the difference if it wasn't working at all. Link to comment Share on other sites More sharing options...
newhome Posted June 20, 2018 Share Posted June 20, 2018 5 minutes ago, Nickfromwales said: ( whispers gently ) it's the green pump, behind that one So which is the HRC? The green one or the one I posted further up? And what does the other one do? 2 minutes ago, Nickfromwales said: You do, but I doubt that whomever plumbed the system ran the HRC return pipework all the way to each basin so, although the system works, it's not reducing the delay for hot water as effectively as it could be. Better than nowt though, and you'd soon notice the difference if it wasn't working at all. Aye, it's a bit of a pain but hey at least the hot water arrives eventually. Previously I had none unless the heating was on! Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 20, 2018 Share Posted June 20, 2018 The smaller green one that originally had the cover missing and the wires exposed. That's the HRC pump. The one in the pic is the pump that's heats the PHE so it can produce hot water. Without that pump the PHE would stay cold and you'd get no heat into the cold water going into it. The PHE is an instant water heater but needs heat passing through the primary side of it first so it can pass that heat indirectly to the secondary side. 1 Link to comment Share on other sites More sharing options...
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