Silage Posted September 21, 2017 Share Posted September 21, 2017 (edited) @Nickfromwales Telford seem a good bet for supplying my UVC. As per other post on UFH with rads but I will now site the tank in the cellar and have an external boiler (fluing from the cellar is a pig and looks expensive). So presume new system boiler and UVC or TS. Can't invest in solar now, or air-source hp as no funds left. See system below I got quoted from Greensquare. Should I not have a buffer if going uvc? Edited September 22, 2017 by Nickfromwales Link to comment Share on other sites More sharing options...
Silage Posted September 21, 2017 Author Share Posted September 21, 2017 (edited) @Nickfromwales Edited September 21, 2017 by Silage Link to comment Share on other sites More sharing options...
PeterW Posted September 21, 2017 Share Posted September 21, 2017 UFH needs a buffer or it will short cycle the boiler. Link to comment Share on other sites More sharing options...
Nickfromwales Posted September 21, 2017 Share Posted September 21, 2017 2 hours ago, Silage said: @Nickfromwales Ive missed the deal but looks like Telford are a good bet. As per other post on UFH with rads but I will now site the tank in the cellar and have an external boiler (fluing from the cellar is a pig and looks expensive). So presume new system boiler and UVC or TS. Can't invest in solar now, or air-source hp as no funds left. See system below I got quoted from Greensquare. Should I not have a buffer if going uvc? Solar ( Pv ) can be easily bolted on later down the line . Just get dual immersions on the UVC and one on the buffer and you'll be covered, not just for Pv, but you'll also then be able to survive short-term if you run out of oil. ( assuming you have oil as you mentioned an external boiler ? ). Ps, if you mention my username and the forum Trevor will still give you a discounted rate ?, but you'll have the slight recent increase to bear. They're still very competitive tbh, so not all bad . Link to comment Share on other sites More sharing options...
Nickfromwales Posted September 21, 2017 Share Posted September 21, 2017 1 hour ago, PeterW said: UFH needs a buffer or it will short cycle the boiler. +1 Link to comment Share on other sites More sharing options...
Silage Posted September 21, 2017 Author Share Posted September 21, 2017 Thanks @Nickfromwales and @PeterW. I had thought so but Greensquare view is it's just extra cost. Would the rads be direct feed from the system (oil) boiler then. So the UVC is just for DHW? For 4/5 people , 1 bath , 3 showers say 250l? The ufh is 71m2 so buffer size x? Existing rads x 9 and new ( in MBC build 1st floor) x 2 or 3), estimate about 13kw heating load in all mostly in the old house. Link to comment Share on other sites More sharing options...
Nickfromwales Posted September 21, 2017 Share Posted September 21, 2017 41 minutes ago, Silage said: Thanks @Nickfromwales and @PeterW. I had thought so but Greensquare view is it's just extra cost. Would the rads be direct feed from the system (oil) boiler then. So the UVC is just for DHW? For 4/5 people , 1 bath , 3 showers say 250l? The ufh is 71m2 so buffer size x? Existing rads x 9 and new ( in MBC build 1st floor) x 2 or 3), estimate about 13kw heating load in all mostly in the old house. UVC yes, just DHW. Greensquare are wrong as they've shown in the schematic you posted ( was it their drawing to you? ) that their separating the rads and UFH circuits with zone valves. It would only be ok if the rads were on with the UFH in parallel at all times and even then it would be less than ideal. Oil boilers like to run hard and long and are most efficient when doing so, and they don't modulate like gas and electric units can. An oil boiler firing just to put heat into your small UFH circuit would be unable to match the low demand as the UFH manifold wouldn't allow it to put more than ~35oC in at any time, and even less when the slab has warmed up. Id say a buffer of 120L with oil would be a good match. Link to comment Share on other sites More sharing options...
Silage Posted September 22, 2017 Author Share Posted September 22, 2017 Yes, that's their schematic. So 120l buffer, 250l uvc (maybe 300l as 2 soon to be teenage girls in house?) and rads driven of the boiler direct? Does anyone have a schematic of that with controls? New outdoor boiler probable need to look at make and size (happy with my Grant vortex pro but indoor). Link to comment Share on other sites More sharing options...
Silage Posted October 3, 2017 Author Share Posted October 3, 2017 @Nickfromwales, rads direct off system boiler? Would you put the UFH manifold at the buffer tank, the circuit is 5m away. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 4, 2017 Share Posted October 4, 2017 12 hours ago, Silage said: @Nickfromwales, rads direct off system boiler? Would you put the UFH manifold at the buffer tank, the circuit is 5m away. If you can easily get the UFH loops to terminate at the buffer then keep it all together, but if it's far easier to remotely mount the manifold then do so, plus even though you'll get losses off the additional connective pipework when the heating is running it'll be adventitious loss. Run the rads off the boiler by all means but make sure there is a 22mm gate valve across the flow and return of the rad feeds ( AFTER the 2-port valve ) so you can introduce a little bypass. Essential with an oil boiler as it wont modulate and would suffer when the house is up to temp and the thermostatic rad valves are only partially open or closed. Getting the house up to temp is a doddle, it's how to manage things when it's up to temp and idling is the real PITA. Link to comment Share on other sites More sharing options...
Silage Posted October 6, 2017 Author Share Posted October 6, 2017 @Nickfromwales, are you saying that the rads would be better off the bufffer then? Is that why you suggetsed 120L? Otherwise Tevor suggested a 90L for just UFH (70 m2). Trevor also pointed me to merchants such as Cylinders by Choice rather than direct sales. @PeterW does you buffer supply just UFH? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 7, 2017 Share Posted October 7, 2017 22 hours ago, Silage said: @Nickfromwales, are you saying that the rads would be better off the bufffer then? Is that why you suggetsed 120L? Otherwise Tevor suggested a 90L for just UFH (70 m2). Trevor also pointed me to merchants such as Cylinders by Choice rather than direct sales. @PeterW does you buffer supply just UFH? I suggested 120l because oil likes a long full burn, so the boiler combustion chamber, baffles and other intervals all get up to temp and it burns clean. You could feed the rads off the buffer TBH, and may be the better solution. I'd recommend feeding them via a pump and TMV so you can cap the max surface temp of the rads, as even direct off the boiler they'd probably be uncomfortablly hot and overshoot the room stat set point. Link to comment Share on other sites More sharing options...
Silage Posted October 11, 2017 Author Share Posted October 11, 2017 @Nickfromwales is my schematic anything close? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 11, 2017 Share Posted October 11, 2017 (edited) Return for the buffer seems to tee back into the boiler flow? TMV for the rads has to have the flow and the return tappings from the buffer connected to it. Return tees off to pick up the 'cold' port of the TMV and then carries on to be the group return of all the rads, with rads flow coming from the 'mix' port of the TMV via the pump. Components are in order just the plumbing of flow / return aren't schematically correct. Getting close though If your struggling I'll sketch something later. Is the existing part draughty / poorly insulted or have you beefed things up there ? Edited October 11, 2017 by Nickfromwales Link to comment Share on other sites More sharing options...
Silage Posted October 12, 2017 Author Share Posted October 12, 2017 @Nickfromwales thanks. I've only got PowerPoint so difficult to sketch in it. Yes I see what you're seeing but I think it's just my drawing. The return from the buffer should go to the other side of the boiler pump as should the return from the uvc. A sketch would be great if you have time, advice on controls even better. The existing is drafty in comparison, will work on it in the future but esimated that it takes 12kw vs 2.5 kw for the new! Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 12, 2017 Share Posted October 12, 2017 46 minutes ago, Silage said: @Nickfromwales thanks. I've only got PowerPoint so difficult to sketch in it. Yes I see what you're seeing but I think it's just my drawing. The return from the buffer should go to the other side of the boiler pump as should the return from the uvc. A sketch would be great if you have time, advice on controls even better. The existing is drafty in comparison, will work on it in the future but esimated that it takes 12kw vs 2.5 kw for the new! It may be a good idea to have two TMV's and two pumps, one setup for each radiator circuit so you can choose a higher temp for the cooler original part of the house and a lower temp for the new area. Either that, or run one TMV for the rads, set a lot higher to satisfy the cooler area, and then downsize the new rads to give off less heat for the same temp. Balancing the heat delivery off one rad TMV may be a bit crude. Sketch to follow tomorrow eve, what do you need to know about the controls ? What make / model is the boiler ( so I can see if it needs to do pump overrun ) ? Link to comment Share on other sites More sharing options...
Silage Posted October 13, 2017 Author Share Posted October 13, 2017 As I'm now moving the boiler outdoor then was looking at an outdoor version of what I have, Grant 15/26 Vortex Pro outdoor system boiler unless you recommend otherwise. Those were heat figures,, actually I got more like 2.9kw (primarily due to the glass link with the old house so could be a bit more) + 12kw and I guess add 3kw for DHW? Controls wise, room stat per zone and one for ufh I guess or would you go whole hog with Evohome and rad valuable etc, probably ££££! Link to comment Share on other sites More sharing options...
Silage Posted October 16, 2017 Author Share Posted October 16, 2017 @Nickfromwales, like this? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 16, 2017 Share Posted October 16, 2017 Add the return from the UFH pump to the buffer and you've got yourself a blue peter badge. Link to comment Share on other sites More sharing options...
Silage Posted October 17, 2017 Author Share Posted October 17, 2017 High praise indeed @Nickfromwales. now would you use the same tappings for rads and ufh as below or seperate? What other components are missing? Link to comment Share on other sites More sharing options...
CC45 Posted October 17, 2017 Share Posted October 17, 2017 Should the hot feed to the buffer go in above the return? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 17, 2017 Share Posted October 17, 2017 23 minutes ago, CC45 said: Should the hot feed to the buffer go in above the return? I think we're in the provisional 'join the dots' stage at the mo . The tappings will come on the cylinder already labelled / in the right place . Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 17, 2017 Share Posted October 17, 2017 1 hour ago, Silage said: High praise indeed @Nickfromwales. now would you use the same tappings for rads and ufh as below or seperate? What other components If your going to buy a buffer, then get two pairs of tappings, one for rads and one for Ufh. You don't really need them to be separate tbh, but if you do tee them off one pair of tappings then each flow pipe will need a single-check non return valve so when one pump is running and the other isn't, the one running can't pull cool or cold water back out of the other circuit . Other than fine tuning what actually connects and exactly where, your looking good. Link to comment Share on other sites More sharing options...
Silage Posted October 18, 2017 Author Share Posted October 18, 2017 Thanks @Nickfromwales, invaluable advice as always. @CC45 thanks for the post, yes it was join the dots but point taken. @Nickfromwalesany view on boiler make, leaning to what I know so Grant, and if you have better schematic then I'd welcome it. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 18, 2017 Share Posted October 18, 2017 16 minutes ago, Silage said: Thanks @Nickfromwales, invaluable advice as always. @CC45 thanks for the post, yes it was join the dots but point taken. @Nickfromwalesany view on boiler make, leaning to what I know so Grant, and if you have better schematic then I'd welcome it. Grant is a great boiler, and easily as robust as the Worcester Bosch, plus a good few ? cheaper. Link to comment Share on other sites More sharing options...
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