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  1. HI Everyone, I have a large 3 bed 2nd floor flat which cannot have gas. I had it refurbished 3 years ago. I took the decision rightly or wrongly to install water piped underfloor heating with a 14.4Kw electric boiler. Sadly I did not project manage the job and the builders were not good at all. They never checked the floor levels before they installed the underfloor heating, and ended up cheating in two of the largest rooms by pouring latex over the top of the heating to get rid of the undulations in the floor. They have since gone bust:-( My issue is the heating is so expensive to run. I am facing an annual electric bill of £8000 or more now, and that is with the cheapest supplier I can find. So I am looking at all of my options to try and reduce the cost. I know I can improve the insulation in the apartment, as there are a lot of cavities around the walls, as being top floor I have vaulted ceilings in every room. Whilst the loft is fully insulated, the purchase of a thermal imaging camera as shown that there are big areas around the sides of most rooms which could not be as easily accessed, and were left by my lovely builders. But insulation aside, I need to try and find a more energy efficient way to heat my home as this is killing me I have considered a heat pump boiler, but I do not believe I would be allowed to install the outside unit here as being a block of flats, putting anything outside is a no go. I have spoken to a heat pump installer who has informed me that the unit cannot be installed in a loft, even if I created a well ventilated area, as it still will not be enough air circulation etc. The boiler I have is slimJim (see link below), I am wondering whether there are other more efficient electric boilers out there, or are they pretty much the same? I am really struggling to think of any other options tbh, and wondered whether any of you guys who are much more knowledgeable might be able to help. I might freeze next winter if not!!! https://www.electric-heatingcompany.co.uk/electric-boilers/slimjim-electic-boilers/?gclid=CjwKCAiAyPyQBhB6EiwAFUuakt2EDYDZtRTPhzZ3ym_crE4Lz4C9swJ_SAN-VDW_ae9Li3hxhRprCBoCorUQAvD_BwE
  2. Hi, I need some advice on what wet UFH system to get for our renovation of a 1970s 3 bed bungalow. The house had subsidence so in the process of fixing that the floors were dug up and replaced with the following construction: hardcore base, membrane, 150mm insulation, concrete finish. Unfortunately we had no say in this setup so we're stuck with it now. We're left with a 40-50mm gap between the concrete and the base of the front door, which obviously limits what we can do with UFH. There are of course low-profile retrofit UFH options and we'd have liked to have gone with the Nu-Heat LoPro Max with self levelling compound but that is way too expensive for our budget (double what we want to pay). What are our other options, especially considering our 40-50mm gap, and the 150mm insulation beneath the concrete? I've seen the pre-cut boards that pipes are laid in which have no compound/screed on top, would these work well enough with our floor construction? Or should we go down the normal route with pipes in screed but only have 40mm thickness? Insulation below a concrete slab means the concrete becomes a part of the thermal mass, so because it has a slow response time would it make sense for the UFH to be run continuously? We'll be installing an air-source heat pump together with insulation above the ceiling and on the outside of the house with a render and/or cladding, so would this help with the response time and/or be sufficient to run continuously or intermittently? Any help would be really appreciated!
  3. Hi - I'm extending my kitchen/diner and want to install UFH. Its extending by 50%, so will have half existing concrete floor and half new floor. The floor in the new bit is yet to be done. The cost of digging out the existing floor is a LOT - I'd like to avoid this if i can. A couple of companies I've seen advertised lay UFH into existing concrete floors by cutting channels and laying the pipe inside. The house was built in 2002, so the existing floor (should) be reasonably well insulated. Example companies: https://www.outsourcedenergy.co.uk/in-cut-underfloor-heating/ and https://www.jk-gb.com/jk-in-ground-ufh.php Has anyone had any experience of this method?
  4. I am in the process of building a timber building in the garden and am looking into electric UFH instead of an electric heater. For context, the building is a suspended timber frame on 16 individual concrete blocks. I currently have 100mm Celotex insulation between joists and have placed 11mm OSB3 on top to give me my flat floor. I then plan to use laminate flooring on top. What are my best options here… 1 - do/can I lift up the OSB and place the UFH directly on the celotex insulation and screed over? 2 - do I install on top of the OSB and then screed? 3 - do I need to add another insulation board on top of the OSB and then the UFH with screed? Any advice would be greatly appreciated! Regards, Dan
  5. Hello, I’m living in a new build, approx 6 years old, with underfloor heating. Up to about a month ago everything was working well, and the house was toasty. Over the last month, the downstairs floors are failing to heat up. When I look at the manifold, there is hot water at 50 degrees coming from the boiler, but all the return flows for all circuits are cold. All of the circuits are calling for heat and never get up to temperature. I got a plumber out, he replaced the pump on th manifold, that has made no difference at all. Next I flushed all of the circuits to remove any air, again this has made no difference. As a final test, I have closed all but one circuit and am waiting to see if that heats up. Failing that I am at a loss as to what the problem could be and am looking for some advice. regards, matthew
  6. Hi All, We're been living in a new build property for the past 2 years without any obvious heating issues. We've an underfloor heating system that's split across 4 rooms, and is driven by a Daikin ASHP. I've occasionally had to take the actuators off in order to release stuck pins after periods of minimal heating activity, but always noticed that the flow valves show 0 flow when the system is on or off. When pressing the zone pin down, the associated flow meter bounces and a knocking sound is heard through the pipe. After watching a few videos online, I wondered if the system had been connected up around the wrong way, but couldn't find confirmation anywhere. When the system is running, if I manually depress one of the pins for about 30 seconds and take temperature readings off the pipes, I see 37 degrees beneath the actuator at the bottom of the manifold .At the top, I see 26 degrees under the flow indicator for the same loop (see attached photos). Am I correct in thinking the flow into the manifold is around the wrong way? If so, apart from not giving an accurate flow indication, does this cause any problems? The house is certainly warm enough through colder periods (22-23 degrees) but I wondered if the system would be as efficient as possible in this configuration? Any advice gratefully appreciated. Thanks, Ben
  7. OK, so we have recently moved into a house which has underfloor heating installed throughout and generally it works really well. The system is fed from the hot water boiler. There are two manifolds, one for upstairs and one for downstairs. Both manifolds have pump which drives the water into the manifold. Upstairs, we have no problems with. Downstairs has three zones, Kitchen, Living Room and Utility/Bathroom. The Manifold is shown in the Manifold_PreStart.jpg file which is how it looks when no heating is on. Heating comes on at 6pm and at that point, the pump starts, shown by the red light in the Manifold_PostStart.jpg image. A few minutes after starting, we get a thumping noise seemingly from the manifold but it is difficult to exactly pin down. I have a video of it which is on YouTube here: - noise starts about 55s into the video. The thumping lasts a few seconds, probably less than 10 and is kinda juddery in nature, its sort of a duh-duh-dumm, duh-dumm. The past few days I have been experimenting with different zones demanding heat via thermostats and when a single room (e.g. the kitchen) is the only one demanding heat from the system, then there is no juddering or thumping. Only when multiple rooms are demanding heat, does the noise occur. For example, today, we had the kitchen and the utility requesting heat and the thumping happened. I don't know much about the system as I didn't install it and there are no manuals etc, but it looks to be mostly Emmeti products. Another thing with this downstairs manifold is that the top "Robot" dial is warped a bit. This dial seemingly measures temperature of the water going into the system. See Warped.jpg. Any idea why this could look like this? Heating is currently on at pressure in the system seems to be about 1.7bar Any ideas what could be going on in this system? The floors get warm just fine by the way. Thanks
  8. Hi, I was hoping to get feedback from members who have polished concrete flooring at 75mm (or close to depth) above underfloor heating. I want to maximise my sub floor insulation thus dropping from 100mm recommended by my contractor to 75mm (I have another post getting insulation advice and was hoping here to gain advice from members who maybe have a 75mm slab or close too) I am getting ready for the conversation tomorrow morning with the potential concrete provider and our contractor and was hoping to get advice from others who have polished a 75mm slab on the their experience regarding pros and cons. Many thanks, Joe
  9. Hi. I have a new underfloor system which got 4 zones, although they are quite close and not really necessary to split. I wonder how I can control it best via Tado and or Alexa. I would like to turn the underfloor heating off when a max temp reached and/or over night. As I have 4 zones it looks like I would need 4 wired Tado Thermostats, which is crazy. Is there not a way to turn of for example the pump via Tado. or if not can I just turn of the pump with a smart socket using the thermostat temperature via Alexa for example? Thank you in advance for your thoughts
  10. So I had some Underfloor heating (re)installed in my kitchen/diner. With the thermostat set to 19C, the floor in the kitchen gets up to about 33C (measured with a gun) while the larger living area rarely gets to about 24C. This isn't too comfortable underfoot and I'd rather the kitchen wan't being heated so much, food etc. The whole area is one zone from the manifold. The water temperature at the manifold is set to minimum (35C) but the manifold temperature gauge says 50-55C when the system is running. the engineer that installed it said to try turning the zone's flow rate down, which seemed to make it worse. I tried turning it up but there is still a big difference between these areas. Is there anything else I can try? 55C seems a bit hot from what I've read, but I don't know how to turn the temperature down any more.
  11. While tinkering with the flow meters on my ground floor UFH manifold today the hot water came on. I've heard of hot water priority and I think this is how my system is set up. I noticed, however, that the manifold pump was still running, the actuators were all energised but the flow meters all showed no flow. At this point the manifold pressure was higher than normal too. This seems wrong to me as the pump is working but unable to circulate water through the system as the heating zone valve is closed (as it should be in). The micro switch on the heating zone valve seems to be working as the pumps in the heating and hot water tank cupboard come on when it energises - as an additional point i'm curious about, there are two red Grundfos pumps in that cupboard and they both come on when the hot water or heating are on - is this correct? I've always assumed that one was for the hot water system (indirect unvented cylinder heated by ASHP) and the other for the heating (all UFH heated by ASHP) but maybe they are meant to be on at the same time? Perhaps one is a send pump, one a return pump? I've attached a photo in case anyone is kind enough to take a look. So, in summary should the UFH manifold pump and actuators be de-energised if the heating zone valve is closed due to the hot water priority? And should both grundfos pumps be running at the same time when the hot water or heating are running? Thanks for any help anyone can give me.
  12. Hello, I am looking for an underfloor heating technician or installer who can help with controls queries in the Middlesborough or Newcastle area. Can anyone recomend someone who will be able to help me out. Look forward to your support Buildhub team. Thanks RHayes
  13. This is driving me insane.. I have a wet underfloor heating system, with Honeywell Evohome zoning. Most zones work fine and I believe all zones are labelled correctly. I have one room where the heating is hardly ever used (think I've had it on twice in 2 years), but wanted it on over Christmas. Despite the controller working, the room does not show any signs of heating (can’t feel anything underfoot). This is even after leaving heating on for days. There are two circuits in this room (dunno why, it’s not the biggest room by far), and both show full flow when on. Grabbing the pipes, flows and returns are hot in both loops which to me indicates nothing is blocked, so why won't it heat up?
  14. Hi all, long time lurker but now a registered member. I've found this to be a fantastic resource for helping with projects and troubleshooting about the house. I've noticed that one of the loops on my ground floor Emmeti Topway UFH manifold (I'll call it loop 1 as its the first loop after the pump - pic attached) is not getting warm on the return side even after being on for a long time at max flow. The other two loops get warm fairly quickly. I've found that shutting loops 2 and 3 off, loop 1 will get to a max if 4 l/min with the flow meter wide open. The other two will bottom out the flow meter (>5l/min) opened wide with the other two shut down. Doing this experiment I can hear the automatic bypass valve in the system is letting by when just loop 1 is full open, whereas if just loop 2 or loop 3 is wide open then it's quiet and not allowing flow through suggesting that loop 1 is restricted compared to loops 2 and 3. I've had the actuator off to test if the pin being depressed stops the flow, which it does. This says to me that water IS moving all the way through the loop. I've come to the conclusion that the loop is air locked, not blocking flow but significantly reducing it. Thing is, if the flow meter is saying 4l/min, wouldn't that be sufficient to feel warmth in the return pipe? Or is it the case that if the loop is air locked the velocity of the water is high going past the flow meter paddle but getting severely restricted further along the pipe where the air is. Or am I barking up the wrong tree with the air lock hypothesis? Any help would be greatly appreciated. I'm not sure the loop in question has ever worked properly since we've lived in the house so it would be a good feeling to get it working.
  15. Hello, I am completely new to the building control process, stumbling my way through, any help very appreciated... I have a maisonette flat situated on the ground and first floors of a 4 storey residential block. The block is a reinforced concrete frame construction. All floors are reinforced concrete slab, with uninsulated screed over the slab. I want to remove the existing screed. Replacing with floor insulation, then a finished concrete floor containing underflooring pipes. I understand from LB1 the new floor should ideally meet a U-value of 0.25 W/m²K, "feasibility" aside. Q1.A How to calculate the U-value of the ground floor? Is this a correct approach? https://warmafloor.co.uk/support-centre/u-values/ is a guide to calculation of the U-Value of the uninsulated floor. based on The IP 3/90 formula is U = 0.05 + 1.65(P/A) – 0.6(P/A)² Where: U = U-Value of the uninsulated floor (W/m²K). P = Length of the exposed perimeter (m). A = Area of the floor (m²) https://insulation-uk.com/member/u-value-calc is an example of a insulation manufacturer provided calculator I have cross compared and they line-up close enough. Q2.A How to calculate the U-value of the first floors within the same dwelling? I haven't been able to find any guides how to do this Whilst it seems a U-value of 0.25 W/m²K still applies, I would assume that first floors within the same property would require less insulation?? the heat only really escapes from thermal bridging of the floor with the wall, heat wasted downstairs is in the same property?? and/or the room below can be assumed to also be heated or normal room temperature, so there won't be such a large temperature difference, so less insulation is needed?? http://files.nu-heat.co.uk/core/media/media.nl?id=237176&c=472052&h=f809f347f001eb168007&_xt=.pdf this datasheet from a underfloor heating company states "In ground floors the insulation beneath the screed should be 70mm ‘Celotex’ or equivalent, or conform to Part L of the Building Regulations; whichever is greater. In upper floors insulation should be to a minimum of 30mm ‘Celotex’ or equivalent to prevent downward heat transmission" Q2.B can anybody link to a formula or calculator to use? Q2.C or is the calculation just the combined U values of the concrete slab + floor insulation? any help very appreciated : )
  16. Hello, Does anybody know the U-Value required when retrofitting / renovating underfloor heating? There seems to be plenty of resources talking about new builds but finding it hard to find any definitive information for retrofit. For my specific property, I have a ground and first floor. Both having a concrete slab floor with screed over it. I will remove the screed, then add insulation, then UFH pipes, then concrete poured over. Trying to work out how much insulation I need. I'm assuming less required for the first floor. Once I determine the maximum U-value permissible for building regulations, I can use various services such as this U-Value calculator to work out how much of what insulation I need. Any help appreciated!
  17. Hi all, I am currently in the middle of a new build (roof is now on). I need to start making decisions on heating/plumbing and I wanted to get some advice before proceeding. My idea is to use off-peak power supplemented with a solar array to run 2x Sunamps for DHW and UFH. The house will have a wood-burning stove, so although I will install UHF plumbing during construction, I might not utilize unless we feel we need it. quick info: - 2 bedroom Bungalow 120m2, well insulated (200mm EWI), triple-glazed, good air-tightness. - I plan to use Sunamp UniQ9 HW+iPV for DHW and another for UHF (UHF will be in two bathrooms and kitchen approx 40m2) - 2.3kw solar array (flat roof mounted) - wood burning stove 5-8kw Some questions I have so far: For DHW, am I right in thinking I need a unvented pressurised system for this set-up... as a pump is needed to draw water through the Sunamp? Is there any need for an expensive solar PV diverter? Surely I can just have a switch with a timer for sunrise/sunset after the inverter? Thanks everyone!! --
  18. Hi, So I can’t find any solid information on this topic. For context, I am wanting tiles floor with underfloor heating from the kitchen into the living/dining room (joining rooms via a door) so basically the whole downstairs. While having a new kitchen installed prior to tiling I was advised to lay some insulation backer boards directly onto the existing floor boards by using flexible tile adhesive and screws with washers. I am now at a stage where I can continue laying the insulation boards through to the living room ready to then continue the process of, electric UFH mats, a self levelling screed and then tiles. My issue is, after laying the boards in the kitchen directly onto the floor boards, the living room has plywood sheets down to which I now am thinking would of been better to lay the insulation boards on to as oppose to directly to floorboards. So what’s the correct way from now? Do I lift the ply in the living room and carry on with the adhesive and boards, or have I messed up already in the kitchen and need to track back. Any help would be greatly appreciated, thanks!
  19. Hi All, I was wondering if at all possible i could obtain some advice 6 weeks ago my builder put underfloor heating (wet) in my new extension in place of radiators 6.5m by 4m. I remember asking him on the day what mix he was using and he said it was a 6 to 1 with fibre glass to aid strength. The floor was laid on a dryish mix by a professional screeder and the floor underneath is block and beam. Unfortunately yesterday i noticed the floor has many cracks. Anything from 5 inches to 2 feet. the cracks are in the middle of the floor in a couple of other places nearby. The cracks are scraggy(like lightning) and not straight. They spur off in multiple directions. If I run my finger in the crack I can run off the top layer so it doe appear sandy. I know the floor hasn't dryed too quickly as the weather has been aweful these last few weeks and we didn't walk on it for at least 3 days after it was laid. We haven't even had the manifold installed so i know the floor hasn't been heated up too quickly. It's my aim to lay Karndean vinyl glued floor tile on the top of the screed but I don't think it's possible with the floor cracking up. Is this right? The questions I have are. 1, as it's already cracking should I request the floor be taken up and relaid using a heavier mix? 2, can the floor still be repaired in sections or should I even consider allowing this? 3, it is normal for this to happen. My limited knowledge says it probably isn't? To make matters worse I have the kitchen arriving in 10 days but I'm reluctant to take delivery if I know the floor needs to come up and be relaid again. thanks again for listening. Any advice you could provide would be very appreciated. Rowly
  20. Good Evening, I am building a new outbuilding in my back garden. I am trying to figure out what the best electric heating solution (CH + HW) would be and I would like to ask you for your opinions here. The outbuilding will contain an office, a gym and a small bathroom with a steam shower unit and a sink as per the plan below. It will be used throughout the year on a pretty much daily basis. I initially thought about using electric heating mats for my UFH and a small boiler for my hot water needs but now I think there may be a better, more cost effective solution. I have seen a number of threads talking about ASHP, Ampec flow boilers and Willis heaters. It made me think about fitting a wet underfloor heating system and using one of the solutions but honestly speaking I am not sure what would be best as my knowledge and experience is limited. I would be very grateful for any advice. Martin
  21. Hi, We have just had a new underfloor heating system installed and would like some feedback on the quality of work. We have a retrofit installation with insulation panels that has traces in it. Soon there should be a latex screed going down but the company doing the screed has said they cannot do anything until the insulation boards have been stuck down and the edges sealed so the boards don't float up. When the board were put down no adhesive was used, is this normal? Also the boards were not cut to the shape of the rooms and gaps were left. On the advise of the screed company the plumbers were asked to come back and fill them in as a huge amount of screed would be needed to fill them. The guys came back and filled in the gaps with boards they cut in to random piece and put in but again did not fix down. Finally they used some expanding foam around the edges but the board lifted due to not being stuck down. Anyway I have included some pictures to let you see for yourselves. Thanks https://ibb.co/St199JD https://ibb.co/svWfn1T https://ibb.co/7vC4MKv https://ibb.co/xjJmBr0 https://ibb.co/5WBZQgh https://ibb.co/TKhrChX https://ibb.co/hsGkkMB https://ibb.co/fpxDKKd
  22. Hi Folks, This is my first post and sorry it is long: please be patient with me as this has been a long term problem. The below has taken a long time to get to due to complacent builder not wanting to help and heating contractor delays who could only carry out tests in winter, etc. As such, for simplicity I will just stick to the facts regardless of the duration it has taken. I bought a new build flat in 2016 with a NIBE F205P heat pump and underfloor heating (UFH). I always wanted to get a nice carpet fitted and I was aware of the combined underlay and carpet tog value rule of not exceeding 2.5. However, I stupidly laid combined tog of 2.8 and had heating issues- the flat would never reach the desired temp of 21 degrees and it was rinsing my electric. In light of this, I changed my carpet to Revlon 90 Scorpius Invictus (tog 1.3) and kept my Duralay King UFH underlay (tog 0.8) for a combined tog of 2.1- it has made no difference whatsoever and the same problems occur even on relatively mild winter/autumn days. On freezing cold days, the flat never stands a chance and is often be 3 degrees off target temperature. Please keep in mind that this problem happens with the NIBE on both setting 1 i.e. heat pump, and 2 i.e. heat pump and immersion (apologies if terminology is slightly incorrect there). So I have a double whammy of no heat but rinsing electric because it doesn't hit the thermostat temp of 21 degrees. Last winter, the heating contractor (who despite the long duration, has tried to be helpful through constant checking, servicing, etc) arranged an investigation of my problem by a third party using both a thermal camera test and laser thermometer. This was done to see if my carpet and underlay was the problem. This test revealed that with the carpet and underlay pealed back, the bare naked wooden floor was outputting 23 degrees. The independent chap informed me that if the system was designed to keep the rooms at 21 degrees, there would need to be a differential of at least +5 degrees meaning the bare floor needed to be 26 degrees minimum to punch through the wooden floor, underlay and carpet. In that moment, the 'heating contractor' who installed it revealed that the 'builder' instructed them to install the heating water pipes “UNDERNEATH” the sound proofing. Sorry but does that not sound like madness? Surely this is why I am having problems and the usual rule of 'do not exceed tog 2.5' no longer applies because there is an extra barrier i.e. the sound proofing. So now I cannot predict what combined tog to install as clearly the heating is not producing the necessary heat, arguably because of the sound proofing being laid on top! I cannot even install hard flooring as it is against the terms of my lease. I really do not know what to do as no matter what setting I have the NIBE on, it never reaches temperature and therefore rinses the electric, especially on setting 2. I was thinking of contacting NHBC about this as I still have six years left and surely this is a building cock up. My flat is relatively small and as a reference, my electric was £327 for the 3 months of October to January. That is far too much for just me and it’s gonna seriously affect ability to sell or I will get some serious comeback since these faults need to be declared on property information forms when you sell. Any advice? I really am in a quandary ☹️. Thank you so much. John
  23. Cast your minds back to ebuild and June 2015. I had a 40sq m concrete slab poured and put in 3x 75m (approx.) loops 16mm pert-al-pert ufh piping (via Wunda). Also got all the parts to go with it. I did my best to connect up the manifold to pressure test the piping after noticeably denting one pipe during the install. It didn’t keep a seal during the pressure test on any of the 3 loops, not just the suspect one. At least they had water in them for the concrete pour. I later found out that for the pipe connections to seal they must be straight. Mine weren’t so the connections were stressed during the test so I’m hoping that’s why they failed. As for the concrete, no idea if the concrete had fibres but it did have a mesh that that the pipes were attached to. And I wasn’t around for the pour itself so no idea if it all floated or they wrecked the pipes during the pour. No bother as the concrete later got dry screed on top. Leaving a nominal 100mm concrete slab + 50mm concrete screed. Could be more could be less, who knows? Do I really want to heat that sort of thickness in a poor thermal spec house? House is brick/block, 100mm boggo cavity batts. I later added an extra (shorter) loop for a section of suspended floor. I insulated as best I could but it was the tilers who screwed the final boards over the top so the integrity of this loop is unknown. This pipe was in spreader trays to give it any chance and I understood the issue of having this loop in the same single zone as my slab loop (lower temp). that’s ok, this was only a small section. So now I have a place in the utility room where I have 8 loose pipe ends – 6 through the floor and 2 through the wall. Nearby is sort of random fused spur outlet – possibly put in for the UFH pump. The gas boiler is a 2015 Baxi duo-tec 33 that runs a conventional radiator system and is wall mounted on the other side of the room, approx. 3m away. The heating piping runs along the base of the wall adjacent to the presumed manifold location. The slab pipes still have the water in them from the abortive pressure test. The floor finish over the UFH is tiles. The tiler insisted we use a decoupling membrane because of the UFH. We didn’t have a liquid screed which is also a bonus. I can’t actually remember what went on top of the suspended bit. It was 18mm ply at least followed by something else, possibly wedi or hardie? So there we are, warts and all - At the very least all the pipe work will need a pressure test and a good flush. - I’m concerned that there are a couple of hollow sounding floor tiles and whether the UFH would affect these or others. Nightmare if more tiles lifted. - When I told the builder that I was putting the pipes in the slab I didn’t expect there to be another 50 mm (min) screed going on top. Is the UFH even worth bother with now? I bet its thicker in places. - Insulation wise I have 100mm EPS and 100mm PIR under the slab but there’s bound to be a few voids and the perimeter insulation was not great, 25mm PIR where present on the exterior walls. At the 3m wide bi fold door, he took the slab up to the outer face bricks. Not so much a cold bridge as a cold multi-lane super highway. And I don’t think I there was any on the edge that went up against the existing house wall either. - Wisely, due to the problems with getting the UFH all fitted we had 2 feature radiators put into the space – 40 sq m fairly low ceiling. Most of the winter they are cranked open to max and we get by but it was pretty cold the either week during the cold snap. this space is our day space, cooking/eating etc. We go to the TV lounge at night or when its cold and crank up the gas fire. Considering how mediocre-ly everything is built, I’m surprised how modest the house running costs are for the 4 of us. Given that I’m already using the boiler to heat 10 radiators I hoping that the UFH will be able to top up the existing rads in this space to make things pleasant without adding a massive demand for heat from the boiler. I try to keep the boiler to below 60 degrees for the heating anyway as any higher and the towel rads in the bathrooms become dangerously hot. - As above with the plumbing and electrics, there needs some thoughts on how to connect it up. First play in this match is to get the manifold out, clean it up and sort an installation position to be able to connect it all up for a proper pressure test and take it from there.
  24. Hi all, Hope you are all alright this crazy year. Very happy I've found this forum. After many years of saving, and looking for more flats than we would ever think we would see, my and my fiance have finally found a flat we could both agree on... Not the easiest of things! The flat we've bought is electric only and the heating is done by electric heaters. The hot water comes from an Elson Coral E which holds 150L. We are looking into putting in underfloor heating to replace the electric heaters. Do you know if an underfloor heating system could even be connected to the Elson Coral E? Since there is outdoor space we would like to, at a later stage, add an Air Source Heat Pump to the system. Is there anything we should consider when choosing the model, type, or brand of underfloor heating so it will integrate well with an ASHP? Any gotchas when it comes to this? Also, the interior space for a new cylinder is quite limited. I read on one ASHP fitters website that they require a full height cabinet. Do you think this could be an issue when converting to an ASHP and a suitable cylinder? These are the dimensions of the Elson Coral E, but as you can see on the picture, there is room for something taller. Width: 560mm Depth: 730mm Height: 820mm I've also attached a close up on the spec sticker of the Elson if that could be useful. Many thanks, Gustaf
  25. I seem to have what must be a common problem when using underfloor heating with a boiler however I haven’t managed to find a standard solution online. The boiler cycles at a high frequency due to the difference in boiler power compared to what the underfloor heating manifold will accept.Setup (underfloor heating recently added by local plumber) – see image below Worcester Greenstar Highflow 440CDI combi boiler (Central heating power of ~29kW down to ~7.6kW) Radiators upstairs with separate thermostat and actuated valve on the CH flow. Underfloor heating downstairs with separate thermostat and actuated valve on the CH flow. Manifold including recirculation pump and mixer valve to maintain the inlet manifold temperature at ~40C. " class="bbCodeImage LbImage" alt="" data-url="http://<a href="https://ibb.co/0DLwm3M"><img src="https://i.ibb.co/tm6dQ5s/UFH-current.jpg" alt="UFH-current" border="0"></a>" />IssueThe Combi boiler cannot modulate low enough when running the underfloor heating on it’s own therefore it cycles frequently on and off. At a high level, The thermostatic valve on the underfloor heating manifold gets close to the required temperature and throttles flow from the boiler. Boiler flow then bypasses the manifold through the pressure relief circuit and causes the boiler flame to turn off. The flow temperature drops The thermostatic valve on the underfloor heating manifold then starts to open because it’s not getting heat, pulling in cool flow and opening more and more. The boiler restarts when it’s anti cycling timer or temperature limits have been reached and quickly exceeds the underfloor heating thermostatic control valve temperature so the process restarts. If the anti cycle timer is put to it’s minimum of 1 minute, the boiler will run for 1 minute and turn off for one minute (the run time will further reduce when the underfloor heating gets up to temperature). At this frequency the flow temperature remains above the temperature setting of the underfloor heating thermostatic valve so the underfloor is happy.I assume that this boiler operation isn’t efficient and I doubt it’s doing the boiler any favours?When the radiators are operated concurrently with the underfloor heating the CH flow temperature remain stable and the system works nicely.Variables currently available in the system Boiler cycle time or temperature limit, currently 1 minute – If this is increased above 1 minute the underfloor manifold pulls in low temperature water as it cycles and therefore takes a long time to heat up. CH flow temperature, currently 60C – If this is increased it takes a little longer for the boiler to achieve the temperature however an increase of 10C only added 25s to the cycle time (by the time the high temperatures are achieved the boiler is mostly short circuiting around the bypass). Boiler pump speed, currently set to three – Assume a reduction would result in higher temperatures (lower flowrate with the same burner rate?) may also impact on the boiler/radiator operation? Boiler pump operation modes – Don’t know enough Underfloor heating pump speed, currently set to three – Don’t think this will have a significant affect. Underfloor heating thermostatic valve, currently 40C – Increasing this temperature risks overheating the engineered wood flooring. Next steps – help please! Is it a problem to leave the boiler cycling so frequently (1 min on then 1 min off)? Can any of the existing settings be adjusted to help? If current operation is a problem the only significant improvement I can think of is to add thermal mass between the boiler and underfloor heating manifold as follows (see image), any tips on these or is there a better alternative? a. Add pressurised tank (are these referred to as heat banks/or thermal stores?) upstream of the underfloor heating bypass loop. b. Draw the underfloor heating flow through the heat store in the boiler. This is the wild card option and I don’t like it because a connection would need to be made within the boiler (although it is accessible) and there may be an unforeseen impact on the hot water supply. I’ve mentioned it because it wouldn’t require another tank to locate, continually heat or pay for! " class="bbCodeImage LbImage" alt="" data-url="http://<a href="https://ibb.co/bLpkNgq"><img src="https://i.ibb.co/6b6kDRV/UFH-options.jpg" alt="UFH-options" border="0"></a>" />
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