bassanclan Posted October 12, 2016 Share Posted October 12, 2016 I'm considering the layout for the plumbing system. 5/6 bedroom house with 2 bathrooms, 2 ensuite showers and one downstairs shower. I'm considering a thermal store around 500 litres. I like the idea of the short delay in getting hot water associated with a recirculating hot water system, but I'm concerned that the shower performance could suffer if two people turn on the shower at the same time. The concern of a radial type system would be the delay in getting hot water given that it is approx 8m from the tank to ensuite 1 (and approx 14 to the kitchen sink). Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2016 Share Posted October 12, 2016 I don't think your two concerns are directly related tbh. Having good flow will have nowt to do with a hot return circuit ( HRC ) or standard plumbing, either will be dependant upon pipe sizing, incoming cold mains pressure and flow rates, and your chosen dhw production unit having a good flow rate through it. Which room is the kitchen under.? Can you post the other floor plan please Link to comment Share on other sites More sharing options...
bassanclan Posted October 12, 2016 Author Share Posted October 12, 2016 The kitchen is under Bedroom 1, the downstairs shower is under e/s2 Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2016 Share Posted October 12, 2016 Let me dart the last 2 kids then I'll come back to this 2 Link to comment Share on other sites More sharing options...
CC45 Posted October 12, 2016 Share Posted October 12, 2016 Thanks for making me laugh Nick Link to comment Share on other sites More sharing options...
Mikey_1980 Posted October 12, 2016 Share Posted October 12, 2016 We have a hot water recirculating system. The run between the two furthest points is approximately 18 metres and we have no issues with two or three showers being used at the same time and people running taps. We have 4 bathrooms and one cloakroom in total with a 300 litre UVC Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2016 Share Posted October 12, 2016 Ok. Boiling tap with blended instant hot water for the kitchen sink, with one assuming you'll have a dishwasher?. Write the expense of the tap off against the cost of the HRC and associated pipework / complexity and running costs. Go for radial plumbing throughout and consider a cold mains accumulator to reinforce the flow rates if your incoming supply is less than perfect. The delay to ensuite 1 will only be apparent when you run the basin hot taps after a jimmy riddle / other. That can be reduced by running them in 10mm. The baths and showers will be relatively high flow rate outlets so by the time you've turned the tap on fully and selected your favourite loofa the water will be hot. The thing to observe is reducing the amount of large bore primary pipework prior to the manifolds for the hot feeds. FYI, I previously plumbed a similar sized property and ran a HRC for just the basins. That worked well as there were a few satellite basins ( WC's ) which would have suffered otherwise. I chose to run a well insulated HRC and also decided to continue a spur off the HRC down to the very far away kitchen sink ( pretty similar to your layout tbh ). I ran the HRC at 50oC to keep the temp,high enough for 'dish wash' and then put individual TMV's ( thermostatic blending valves ) at each wash hand basin to reduce the water temp to make it comfortable for hand washing, negating the faffing about between hot and cold. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2016 Share Posted October 12, 2016 43 minutes ago, CC45 said: Thanks for making me laugh Nick Just glad to be providing a service. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2016 Share Posted October 12, 2016 17 minutes ago, Mikey_1980 said: We have a hot water recirculating system. The run between the two furthest points is approximately 18 metres and we have no issues with two or three showers being used at the same time and people running taps. We have 4 bathrooms and one cloakroom in total with a 300 litre UVC Does the hot run in 22mm for the majority and then reduce to 15mm with a 15mm return? Link to comment Share on other sites More sharing options...
bassanclan Posted October 13, 2016 Author Share Posted October 13, 2016 Thanks for your thoughts. Boiling kitchen tap has been given a big thumbs down by "the boss" The kitchen sink is on an island, with the pipework having to run under the beam and insulated block floor, so not ideal and another reason I thought the recirculating system would be a good idea. I'm planning on using a WBS with back boiler, gas system boiler and any excess solar PV, which is why I thought a thermal store was the way to go. 1 Link to comment Share on other sites More sharing options...
Mikey_1980 Posted October 13, 2016 Share Posted October 13, 2016 11 hours ago, Nickfromwales said: Does the hot run in 22mm for the majority and then reduce to 15mm with a 15mm return? Yes exactly this and all run in copper piping Link to comment Share on other sites More sharing options...
jack Posted October 13, 2016 Share Posted October 13, 2016 45 minutes ago, bassanclan said: Boiling kitchen tap has been given a big thumbs down by "the boss" On cost grounds? Must say, I wasn't 100% sure when we chose to install one, and now I wouldn't be without it. Forgot to do veggies for kids' tea? Frozen peas, boiling water tap, done faster than even the microwave can manage! Not to mention the ability to make a cup of tea in about 20 seconds start to finish, which comes in handy if you watch a lot of BBC (no ads). 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 13, 2016 Share Posted October 13, 2016 2 hours ago, Mikey_1980 said: 14 hours ago, Nickfromwales said: Does the hot run in 22mm for the majority and then reduce to 15mm with a 15mm return? Yes exactly this and all run in copper piping. That's the 'normal' way to do it, but has the Achilles heel of long waits if the HRC is ever turned off ( so basically you'd need to run the HRC from dawn to bedtime really ) as you then have bigger dead legs caused by the 22mm pipe runs. Agree that it's a balance, as the 22mm pipe runs give the flow rates for 2 showers etc so if your happy to run the HRC accordingly then a good option as it negates complex radial pipe work. I guess it's the toss up between a passive or dynamic solution, but an HRC is really for quite adverse situations or folk who value convenience before absolute efficiency. Link to comment Share on other sites More sharing options...
Mikey_1980 Posted October 13, 2016 Share Posted October 13, 2016 (edited) We run ours on a 24 hour 7 day a week timed pump which works quite well as there is normall enough water for hand washing during the day with out having to run the taps for ages when the pump shuts off at 9am. Edited October 13, 2016 by Mikey_1980 Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 13, 2016 Share Posted October 13, 2016 1 hour ago, Mikey_1980 said: We run ours on a 24 hour 7 day a week timed pump which works quite well as there is normall enough water for hand washing during the day with out having to run the taps for ages when the pump shuts off at 9am. Could you elaborate a little on that please? Are you saying the water stays warm in the pipes ? The scenario your describing makes having the hot return sound unnecessary. Link to comment Share on other sites More sharing options...
bassanclan Posted October 13, 2016 Author Share Posted October 13, 2016 10 hours ago, jack said: On cost grounds? No, just on a "I don't like the idea of that" someone could scald themselves etc etc Link to comment Share on other sites More sharing options...
bassanclan Posted October 13, 2016 Author Share Posted October 13, 2016 Surely the volume of water contained in a hot water circulating system is not that much. Say 0.3 litres per m (22mm pipe) In my situation I would probably be looking at a total circuit of approx 20m, so approx 6 litres of water. A typical pump might work at 1.8 cubic m per hour (1800litres per hour) so it would take 20 second to pump the 6 litres around a ciruit. I don't know if such a timer exists, but if you could set up a timer to operate the pump for 30 seconds every 30 mins (or however long it takes for the water to cool down) from say 7am - 10pm that would only be 15 minutes of pump operation per day. Link to comment Share on other sites More sharing options...
PeterW Posted October 13, 2016 Share Posted October 13, 2016 10 minutes ago, bassanclan said: Surely the volume of water contained in a hot water circulating system is not that much. Say 0.3 litres per m (22mm pipe) In my situation I would probably be looking at a total circuit of approx 20m, so approx 6 litres of water. A typical pump might work at 1.8 cubic m per hour (1800litres per hour) so it would take 20 second to pump the 6 litres around a ciruit. I don't know if such a timer exists, but if you could set up a timer to operate the pump for 30 seconds every 30 mins (or however long it takes for the water to cool down) from say 7am - 10pm that would only be 15 minutes of pump operation per day. We had a 45m loop of 28mm in a commercial building I used to manage and I put a bog standard 24hr mechanical timer on the pump so it ran 15min/hr from 6am to 11pm. Just doing that (from 24x7) saved around £70 in electricity per year and I've no idea how much LPG as it was on a 300l UVC that definitely cooled overnight. Pipes were insulated too but in a cold roof space. The timer cost £15 ... Link to comment Share on other sites More sharing options...
jack Posted October 13, 2016 Share Posted October 13, 2016 39 minutes ago, bassanclan said: No, just on a "I don't like the idea of that" someone could scald themselves etc etc I wouldn't have believed this was possible until one of our friends' young teenagers someone how managed to turn the boiling water tap on to wash his hands! No serious damage done but a fair bit of shock for all concerned. Personally I'm amazed he got it going at all (there's a knack), and also a bit puzzled about why he used this small tap off to the side rather than the stonking big one in the middle! Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 14, 2016 Share Posted October 14, 2016 19 hours ago, bassanclan said: No, just on a "I don't like the idea of that" someone could scald themselves etc etc There's a higher risk of spilling a full kettle over you and causing horrific injuries than a splash of boiling water on the back of your hand from the instant tap imo. Waiting for the kettle to boil does my nut in so I'm a fan. Link to comment Share on other sites More sharing options...
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