Nickfromwales

Copied over from EB. Formatting to be done ASAP, just grabbing content for now Hot Water System Idea Started by vijay , 28 Jan 2016 05:56 PM Page 1 of 2 1 2 NEXT Register (at top of page) to post reply 28 replies to this topic #1vijay Regular Member Members 413 posts Posted 28 January 2016 - 05:56 PM I have an idea for my heating system for both domestic hot water and also for the UFH and just wanted it to run it by you guys for thoughts. I’ll be looking for a well-insulated air tight build in ICF and the build will be around 700m2 over 3 floors and also a large attached garage with a room above. I plan to use UFH throughout (although I will have to decide if I actually need it on the first and second floor as there is a galleried landing and there is a pretty good flow through the house). I have gas so will have a combi boiler fitted but my idea is to use PV and also a WBS with back boiler to heat the water. The WBS won’t be located in the house but will be in the garage so to not overheat the house. I plan to use offcuts of logs and sawdust that I can get for nothing and are discarded. I’m thinking I would use a large thermal store which can be located under the stairs and will be pretty central. I also wondered if there is any advantage to a second hot water tank in the loft where excess hot water can flow up to and also give me gravity pressure to the taps? Could that work? Cheers Vijay Like This Report post to moderator (eg spam) #2Nickfromwales Short cuts take three times longer.....Fact Moderators 8,182 posts LocationSouth Wales Posted 28 January 2016 - 06:07 PM Open tank for Gravity hot water is a no go. Too many losses and poor pressure unless you fit noisy pumps. I'd fit the TS in the garage and run pipes in a trench to the house, as I've done in the past, and incorporate a hot rerun circuit to give instant hot water to each outlet. The Pv will offset the losses and the extra space and zero latent heat influx by not having a cylinder in the house will be big positives imho. The gas would be to a system boiler, rather than a Combi would it not as your dhw would be provided by the TS Regards, Nick. Edited by Nickfromwales, 28 January 2016 - 06:08 PM. Hide Report post to moderator (eg spam) #3gravelld Regular Member Members 655 posts Posted 28 January 2016 - 06:08 PM Do you have any target heat loss figures and also DHW requirement (which might imply the TS sizing and therefore heat contribution)? "Well insulated" means anything from a modern volume house builder noddy box to... an _actually_ well insulated house. In the latter case, many complain that heat loss from the TS is significant. There are the new PCM heat stores to consider. Like This Report post to moderator (eg spam) #4alexphd1 Regular Member Members 133 posts Posted 28 January 2016 - 06:12 PM How simple things would be to have mains gas on site. Small system boiler and large s/s unveiled cylinder. Have you calculated out the heat requirements? Is the thermal store in the thermal envelope of the building? Like This Report post to moderator (eg spam) #5alexphd1 Regular Member Members 133 posts Posted 28 January 2016 - 06:28 PM I am building a very similar house (large icf to a passive standard) and went through the idea of a log gasification boiler in the garage. I came to the conclusion the extra cost, efficiency loss in the system to accommodate large accumulator and work involved in lighting/cleaning the boiler it wasn't worth it. I even figured out how to import a cheap boiler and get it on to the RHI. In the end I have concentrated on getting heat demand down and picked up a 14kw ashp for £1k on fleeBay. Like This Report post to moderator (eg spam) #6vijay Regular Member Members 413 posts Posted 28 January 2016 - 07:06 PM Nick, I was thinking of a vented tank in the loft as the second tank rather than open (or did you mean vented?) I'd prefer not to have the thermal store in the garage if possible. Could the latent heat not be vented trough the MVHR during the summer? The reason I thought more of a combi is it's more of a back up than used every day, as my way of heating would be the WBS and PV - although I admit to not considering summer when I wouldn't have the WBS on but would obiously still need DHW. Gravelld, No I haven't got any figures yet. Are they given by the SAP accessor? An issue I have is I will be living on my own there but need to future proof it, so any systems I put it will be overkill for me but suitable for a family. The house will be an actual well insulated in ICF U value of 0.15 and tripple glazing. Alexphd1, Yes I as thinkin the thermal store would be in the thermal envelope under the stairs Like This Report post to moderator (eg spam) #7alexphd1 Regular Member Members 133 posts Posted 28 January 2016 - 08:02 PM the sunamp heat battery could be good solution for your thermal store but its not exactly cheap! Other guys on here have 1st hand experience and I myself will be keeping an eye on their report. I wouldn't rely on a MVHR to cool down a area with a thermal store. Again you have mains gas, I wish I had. Like This Report post to moderator (eg spam) #8vijay Regular Member Members 413 posts Posted 28 January 2016 - 09:17 PM I would rather run off grid as much as I possibly can though, hence the WBS/back boiler and PV/immersion heaters Like This Report post to moderator (eg spam) #9jsharris Please ignore all posts by me, some are erroneous Member Blogger 11,461 posts LocationWiltshire/Dorset border Posted 28 January 2016 - 10:34 PM I can positively confirm that MVHR won't get rid of the waste heat from a thermal store in summer. I got rid of our thermal store, in a new build, because try as I might I couldn't find a way to cope with the excess heating effect in summer. The waste heat actually cracked the oak door to the service room and over heated the adjacent bedroom. I tried adding loads of extra insulation to the thermal store, but it still leaked a lot of heat. I've replaced it with a Sunamp PV, which seems to have a very low heat loss, certainly massively less than the thermal store we sold on ebay. Like This Report post to moderator (eg spam) #10vijay Regular Member Members 413 posts Posted 28 January 2016 - 10:55 PM and IIRC from your post, it was from the store and not any pipework wasn't it? How hot did the service room get with the door closed???? Just had another thought, would this be another reason for a second hot tank/thermal store which is much smaller, so it could be used in summer and the main large store closed off? Or just use a combi for summer DHW on demand or have the combi just top up a smaller hot water store which is heated by PV in the summer? (or would that PV heated water feed into the combi, so the combi just tops the already heated water up if need be) Edited by vijay, 28 January 2016 - 11:00 PM. Like This Report post to moderator (eg spam) #11Triassic Advanced Member Members 1,239 posts LocationCumbria Posted 28 January 2016 - 11:01 PM Hi Vijay, I think you need to slow down a bit. Before you do any sort of design you need to know the size of your heating requirement and your SAP assessment should give you this. The other alternative is the look for a copy of Jdharris's heat loss spreadsheet, it's on here somewhere! Fill that in and come back with the results. I have a feeling that if you get the building air tight and well insulated, a lot if the kit you are suggesting will be obsolete. Like This Report post to moderator (eg spam) #12vijay Regular Member Members 413 posts Posted 28 January 2016 - 11:14 PM Hi Triassic, These are just ideas that I've had and I promise my first priority is getting the envelope done right first. I'll be in the house well before I fit any heating so will get a fair idea of how warm/cold it feels. I guess the difficulty for me is not getting my head around a well insulated airtight house as I've only lived in old draughty ones - I hope I'm in for a big shock!!! lol Like This Report post to moderator (eg spam) #13jsharris Please ignore all posts by me, some are erroneous Member Blogger 11,461 posts LocationWiltshire/Dorset border Posted 28 January 2016 - 11:18 PM vijay, on 28 January 2016 - 10:55 PM, said: and IIRC from your post, it was from the store and not any pipework wasn't it? How hot did the service room get with the door closed???? Just had another thought, would this be another reason for a second hot tank/thermal store which is much smaller, so it could be used in summer and the main large store closed off? Or just use a combi for summer DHW on demand or have the combi just top up a smaller hot water store which is heated by PV in the summer? (or would that PV heated water feed into the combi, so the combi just tops the already heated water up if need be) The service room got to over 40 deg C in summer and almost all the heat loss was from the thermal store, rather than the pipework, I took thermal images of it to check. A combi and Sunamp PV with PV panels on the roof and an excess power diverter would be a good option. Like This Report post to moderator (eg spam) #14alexphd1 Regular Member Members 133 posts Posted 28 January 2016 - 11:28 PM I can second the difficulty in getting your head around such a small heating demand for such a large house. Like This Report post to moderator (eg spam) #15vijay Regular Member Members 413 posts Posted 29 January 2016 - 10:45 AM It's almost a dream to think of a warm house!! Like This Report post to moderator (eg spam) #16sketch3d Regular Member Members 376 posts LocationMilton Keynes Posted 29 January 2016 - 11:10 AM Just another thought, IF mains pressure is good, what about inline point of use electric hot water heaters. I know some landlords who swear by them, but have no experience of what they are like in practical use. Advantages I can see are that - There would be be no need for a storage tank. - Only cold water need be routed through the house. - Less water wastage waiting for hot water to come out of the taps. - Cheaper to replace than boilers particularly in hard water areas where heat boiler exchangers furr up. ScrwFix around £140 per unit for a Redring brand. - The house underfloor heating this then charged with a gas combi-boiler doing less work. Disadvantages that come to mind would be where to site the unit in each room requiring hot water. They aren't pretty. Like This Report post to moderator (eg spam) #17gravelld Regular Member Members 655 posts Posted 29 January 2016 - 11:51 AM Jeremy wrote the book on them (see his blog), but you can get modulating ones which would also work alongside other heat sources which would provide the pre-heat. I'd like to see how to design such a system, given DHW requirement, storage technology, other inputs, flow rates and also electrical limitations (single/3 phase). Edited by gravelld, 29 January 2016 - 11:52 AM. Like This Report post to moderator (eg spam) #18AliG Regular Member Members 271 posts Posted 29 January 2016 - 12:31 PM Hi Vijay, What you are building sounds very similar to my place in terms of size and U-Values. Jeremy's heat loss calculator predicted that I only need around 5kw of heat input when it is 0C outside. This is probably negligible relative to what you are used to. If you ran everything off gas you would be talking about maybe £800 a year of which half would be for hot water. I expected to use a similar system you with a TS and solar thermal. Eventually, however, I changed to a UVC and system boiler with solar PV which can provide extra DHW when the heating isn't being used. UVC's seem to be cheaper than TS, and a straightforward system boiler is cheap and also importantly an easily serviceable and replaceable item. When I did the calculations I was only looking at heating costs in the few hundreds per year using gas so the cost of expensive equipment was just wasted. I note that you do say you have a supply of free wood, so you could make it work, but I doubt you would save much after the extra capital costs and I am not sure how much hassle filling it up would be. You could use an ASHP for such a modest heat requirement but again they cost somewhat more than a system boiler and with the premium of electricity to gas don't save any money on running costs. They also get less efficient if you want to use them to heat water and in the winter when it is coldest. Half your heating requirement will likely be hot water. I had the same issue as you with would I actually need UFH in the whole house. My suspicion is that the ground floor would be enough, but for the risk of upsetting my wife and the fact that I couldn't rectify it easily if it was a problem I went for ground and first floor with nothing in the top floor which is under the roof. People may also find it odd if you ever want to sell the house. As I understand it a well insulated house is likely to get very hot under the roof as the heat rises. I think some people have gone for the option of putting in the pipework but not connecting it up. UVC produce pressurised hot water so can be anywhere in the house, I kept it on the ground floor as they are large and heavy and it will make it a lot easier if it ever needs to be replaced. I would size it up depending on how many showers you could have being used simultaneously. I went for 500l as it doesn't really add much cost to have a larger one and it makes life a lot easier when people come to stay. The ability to heat DHW quickly is more likely to drive the size of your boiler than the amount of heating your house needs. If you are planning on having a fireplace, I have found that the large wall inset balanced flue fires that I had assumed I would install produce way too much heat for the house and you have to take this into consideration. My in-laws have in line electric water heaters and they work fantastically well, but depending on your hot water usage the cost to heat it would probably be 3x higher using electricity after taking into account the lower amount of pipe losses. If you are putting in a boiler anyway I don't really see the benefit. You might consider a circulating hot water loop depending on the length of your hot water pipe runs. Like This Report post to moderator (eg spam) #19alexphd1 Regular Member Members 133 posts Posted 29 January 2016 - 12:45 PM I don't know if they would work with pre heated water but a gas water heater could be a option instead of electric. I.e Worcester greenstar hotsprings cwi47. Over 20L @ 35'c rise. Like This Report post to moderator (eg spam) #20joe90 Regular Member Members 847 posts Posted 29 January 2016 - 01:09 PM Electric inline heaters work with warmed/ heated water if they modulate. I plan using one as back up. Like This Report post to moderator (eg spam)

Welcome aboard David For big posts, a few here use a separate machine / text medium ( like word ), and paste it in. This forum has draft auto save but you need to be connected to t'internet in order for it to back up your post ( prior to posting it ). Weve tried it and it works ok, and the text should be there when you go back to type in the editor box. Check your connection prior to 'pausing' midway through a long post. .

Office and General. ?

A big telly in 78 would have been 14"

I can't believe it was only £50. You called them out, so you knew it was coming, deep down, didn't you ?

I doubt if I'd have got on well up your neck of the woods, Dave. I'd have been locked up after being asked for 4 chuffing non return valves on the water supply The BCO's I've met have been really helpful, enthusiastic and 'sensible' tbh. The second they realise I 'know my onions' they backed off and the jobs went much better for it IMHO. I think if BCO's (i) treat you like an idiot, or (ii) get proven to be an idiot by you, then you soon develop a sense of disregard for them and on a self build you'd not suffer as it's your own job so you'll go belt and braces anyway, but if that happens to a builder on a private job, they're just going to try and cut corners to get one over the BCO. A stupid game of cat and mouse IMO.

Fill ya boots

I haven't actually ever had the displeasure of having to do a leak test on the soils and wastes. Last few BCO's were generally impressed enough by the overall standard I displayed, and in most instances I'd gone above their remit, without provocation, so I think I got let off the hook. Last extension was a nice one, and I got the final sign off purely from emailing the BCO photographs of the required items / locations etc. He genuinely didn't come back to site after seeing the build through to to the insulation and roof etc, and only wanted the electricians certificate for conformation of locations of the smoke detectors. B I N G O

Chicken Now you've gone and said it................

Those trays are a wonderfully simple and practical solution. Looking damn good so far

+1. "Where there's a will, there's a way"........the Buildhub way

Until one arrives, I'll try and fill the void.

The adjustable bends Jeremy mentions usually have quite a large collar on each universal joint so can be quite wide, depending on manufacturer. Fwiw, I've done plenty of soil stacks and have always simply pulled the pipe square. Never had a leak or a comeback tbh. You could use a clip at the outer edges of the run, and then use patent band / similar to fix at the elbow I suppose. That would put the bend tight against the wall in the corner and remove 50% of the overshoot. Ive never had a problem using 92's for exact 90o bends, and, if it's 110mm pipe runs, I'm really struggling to see the issue if I'm completely honest. @ProDave Your issue will be worse as there's little to no 'give' in rainwater products I sell on all my exterior work tbh, so can't offer any help here, sorry.

+1. Always avoid protrusions and then the plasterer has a flat clear surface and you get a much better plaster job / finish. That's the reason I first fix all the downlights, with the cables coiled up loosely, and then drill through the plastered ceiling the day after and fish the cables out. Quite easy if you draw a reference 'map' and note the positions down .

He's already sacked ! Didn't fill the screw holes with silicone before putting the screws halfway in, and then another dab behind the screw head before fully tightening. . 8/10 I really don't like seeing compression going onto push fit and with those tails secured in the wall, if the plastic pipe got damaged prior to / during fitting, your buggered. I don't like those odds, especially when your tiled and grouted by that stage. He also didn't mention hand tightening one nut of the shower onto one fully tightened backplate, and then offering the other into a partially tightened backplate to allow some lateral movement. That way if your not dead on 150mm centres ( not the 1500mm he's says ! ) you can still get the second nut on, and then using a long reach pozidriver, you can tighten up the screws accordingly. Once tightened, remove the bar mixer, screw on the covers and refit the bar mixer, and then test. What he also doesn't say is that water can leak back down the pipe work from these kits, so you wouldn't know until a lot of water has gone behind the wall / void. Another reason why I insist on copper, as you can tighten the olive much more firmly. I did like the bit where he says "Lovely!" . Overall he gets a 6/10. Good, but no cigar sorry.

No. Convert to copper prior to exposing the pipe so you can make the pipe off satisfactorily into the compression fittings of the kit I linked. I never terminate push fit of any breed into compression, always convert back to copper first. Have the push fit rising to a Hepworth straight coupler and then ( if you have the depth ) pull a bend mechanically, if not use a Hepworth bend, but you must have copper exposed for the final connection. In most situations, with stud walls, you not be able to bend the push fit pipe at 90o anyway, as the available depth wouldn't allow you to maintain the stated minimum bending radius .

In my spare time of course

I'll elaborate a bit more later, ( when this combis fitted ). ?

Sorry I'm late to the party These are the ones I use. Just fit a couple of 18mm plywood squares where these are to be fixed ( drill the ply to take the pipe centrally ) and that's it. No need for any of the above complexity ( and I used to use the supplied cranked unions when I first started , never again ) and bobs your uncle.

I'd be quite concerned if my architect was basing his preferred construction method on vehicular impact . I'd expect a slightly more 'relevant' argument.....wouldn't you?

Ok, daft question , but what's the appeal of these boilers to the extent that you've chosen to chase this up? They're not mega cheap so what gives?

That's pretty much the point where I'd ask him to shut the door on the way out

A new hand saw such as a Jacksaw is my weapon of choice. Nice wide blade to keep the cut straight and true. The multi tools tend to melt / cut through so be prepared to have to do some extra de-burring if you use that. I do use them for this task occasionally, but only in adverse situations.

2nd place is still a trophy mate

One of a few decent looking ones. http://m.ebay.co.uk/itm/Manthorpe-Tile-Access-Panel-GLTAP-500-/272270041907?nav=SEARCH