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  1. I'm in the early stages of the refurb of a 1917 property in Kent. The rough downstairs floorplan is below - The floor is a real hotchpotch of suspended floor (45% - Green), Previous extension concrete floor ( 35% - Yellow) and New proposed extension (Orange 20%). The current EPC is a horrible 23 and we're looking at using a combination of internal and external insulation to improve this. This may be an opportunity to seal the house (replacing floorboards?) Trying to bring all the potentially different technologies and solutions together is a challenge and every choice seems to lead to a particular specialist supplier that may have a particular axe to grind/product to sell. There is a wealth of knowledge and experience on this forum that I am very glad that I have found. Regards Tet
  2. Finally got the heat pump up and running. After clearing the air locks the system seems ok (?) but just need some reassurance that it is working. The house is obviously very cold (10 degrees) so it is going to take some time to warm up. How long does it take to see some improvement as it went up 1/2 degrees but I also turned on my mvhr today so a few things changed? What have people set the water temp for the ufh? House size is approx 26 x 9 internal floor area and is all ufh on a Passive slab so I know it is going to take a while. When I initially got it running the buffer tank heated up quickly but the blending valve was not adjusted so as soon as i altered that the heated water went into the ufh pipes and all the heat just dissipated so I guess I am after as much info regarding the first time of turning on the ufh and the running of there after, please!! I know you have to warm the slab up slowly but it could'nt get any slower but I am comparing it to rads as I have never experienced wet ufh before. TIA
  3. I've read various threads and views and back and forth and done some calculations based on information I have found here and of course from the very helpful spreadsheets provided by our friend @Jeremy Harris. I had pretty much decided ages ago I would get an 8.5kW Ecodan, which might go up to an 11.2kW ecodan unit. However I have not really advanced it beyond basic assumptions, what others done and some quick back of the fag packet calcs. I'm about to start foundations shortly hence, need to firm up on the UFH design for the in slab pipework and would appreciate some sense checking/ a wee nod that it seems ok. Build is SIPS with Kore insulated foundation, aiming for high levels of airtightness but not near PH (basically as best as I can get it without major hassle), Vent Axia Sentinel MVHR. ASHP which does UFH and DHW (UVC 3-400L tank). Secondary heat source of Log burner (I'm aware it's overkill likely - but I have 2 acres of woods, vaulted ceiling and need a backup in the event power ever went out). I would like to map out the steps in layman's terms to ensure they are right and I have followed it correctly from what I have read, then hopefully the thread can then be followed by others. Step 1 - Heat loss calculation: So I completed the heat loss calculator - see attached. I have a few checks to do on areas and might make minor adjustments but near as dammit it's close enough. I have added the OAT values for my local area (West Scotland, south of Glasgow) from the MET office. Now do I basically just use the 'Total daily heat loss power for average OAT (W)' value to find the maximum based on historical data and that defines the minimum amount of heating system required such below: which seems 3.6kW heat loss for January. The simply - I select a heating system which can supply this amount of heat as a minimum (ignore losses for now). So just simply selecting an 8.5kW unit would do the job easy? Step 2 - UFH design So Having found out the maximum heat loss above (3602W) then we can just plug this into the Heat loss and UFH calculator, which I have also attached. And provides the following output. So essentially, going on bare minimum I would need an UFH system which provides 27.7W/m^2 , based on 130m^2 of floor - so essentially if I don't use some slab area then I need to compensate and adjust the calc. Step 3 - UFH loop spacing So I know the total heat loss, I know how much heat input I have to supply per m^2 if I cover the whole area of 130m^2. So I get loopcad, then draw the circuits. Aiming for counter flow circuits as they provide the best option for even heat distribution, keeping circuits less than 100m in length. Now this is where I get a little lost, I have a figure of 27.7W/m^2 for the whole area to get my required heat input, however how do I correlate that with loopcad and also deciding what my spacing should be?! I have seen @PeterW mention quite a few times about the the spacing had to be adjusted but I am struggling to find the route here to confirm easily what it should be. My loopcad drawing (I've attached my current draft) showing for example 105W/m^2 in my living room, but I'm not sure how this should read in relation to my calculated figure. I'm pretty sure I'll need 200mm centres, but I'd like to ensure that was right. I've some adjustments to make to my circuits, but it's not far away. I was finding that the auto generate function for pipework isn't ideal but it works ok. The garage can be ignored - I ma installing pipework in there pre-empting possible future conversion of that area and hence pipe is cheap, so why not add it now. The manifold will go below the stairs - seems to make sense to me, I have a plant room directly adjacent and was going to put it in there but seemed better to get it out of there as I will have lots of ducts and this would clutter that up. Is it ok to run underneath the stairs? I assume I just have to tell the Joiners not to fit the stairs to the floor with big screws?! Step 4 - Zones I am only having downstairs heating, so it is a single manifold. I would prefer as few zones as possible, but a single zone wont work. I was thinking I can have two /possibly three. Zone 1 - Main family room area Zone 2 - Everywhere else excluding shower room and garage Zone 3 - Shower room Zone 4 - Garage (permanently isolated at the moment. I assume you can have multiple zones on a manifold, and can just split them up by using salus actuators?. So a single thermostat for family room can control three loops (each with an acutator) in that room? and so forth?. It's a long post , and actually I wasn't going to talk about zones but thought it was worth adding in. Thanks. Heat loss calculator - SuperJohnG.xls.xlsx Floor heat loss and UFH calculator - SuperJg.xls.xlsx Looopcad - SuperJohnG.PDF
  4. Right, so following on from my blog entry here where I discuss using Willis heaters to heat up my UFH ( ) I'd initially tested them earlier in the year when I'd set them up and then only in the past 4wks really started to use them for some evening heat in the house and they did their job pretty well (not turned on all the loops yet as there are some rooms that aren't completed yet (north colder part of house). So only switched them on manually for say 2-3 hours each day. Yesterday one of the heaters started 'making noises' that he was not happy, so I switched that one off and left the other one to run. Then today the other one also decided it was not happy. Video below, with aforementioned Willis...'making noises'. 20201112_164008_001.mp4 To me it sounds like a kettle that's trying to boil/simmer with not enough water. I'm suspecting it's scaled up already in this short time. There's no heat coming from the outlet pipes at all and the heaters themselves don't feel warm either. I still have pressure (1.5 bar) so I don't think I have a leak anywhere and no water in pipes. The manual bleed valves indicate there's water in the manifold at least. Any other ideas before I start dismantling the buggers as there's at least 4 compressions I have to bugger about with which were a pain to seal initially? Resident willis heater experts @Nickfromwales, @TerryE ? :-) TIA!
  5. Hi, I had a mid life crisis and decided to rip out the central heating system and install underfloor heating 😀 The project isn't finished yet, but most of the rooms now have heating. This is a retrofit system using overboards with pipes laid in them at 150mm centres. I have a couple of questions that I'd like to get a better understanding of (bit late, I know!). Q1 - Efficient UFH temperature I don't know much about thermal dynamics, so hypothetically, if I have a system that loses 1 degree per hour when the heating is off, and it takes 1 hour to increase the temperature by 1 degree when it is on, would it be more efficient to let the heating go from 21 to 18 over 3 hours and then from 18 to 21 over another 3 hours, or would it be better to go from 21 to 20 and then back to 21 every two hours, or doesn't it make a difference? The reason for this question is that I'm thinking of leaving it polling constantly between 20 and 21 degrees. Q2 - UFH max floor temperature dilemma I currently have the manifold set to 42 degrees. This is taking a lot of time to get up to room temperature (5-8 hours, and it's not even winter yet!). The problem is, if I set the temperature any higher then the floor gets above 27 degrees (tested with an infrared thermometer, although this may be inaccurate?), and as most of the house is laminate, I believe this is not a good idea. I did think about installing floor probes, but I figured that once the floor got above 27 degrees, the heating would cut off until the floor temperature dropped below 27, which may protect the floor, but would defeat the object of trying to heat the house, albeit heat would still be coming from the floor? I also assume that once the temperature drops outside in the winter, the floor won't reach 27 unless I increase the output temperature from the manifold, so it will be a juggling act through the seasons? As you can see, I didn't think this through first 😂 and I hope I haven't left out any vital information in these questions. Still glad I did it though! Regards
  6. Hello guys, I have searched google but I could not find an answer in my attempts to find out why the red cap flow meters of UFH systems are always fixed on top of the manifold, and the actuators are placed below. Could anyone explain, is there a specific reason why is it so? Is it allowed to fix them contrary, and would that have any negative consequence?? Thank you for your answers.
  7. Hi there, I've a 125m2 extension being erected next year with a pretty basic floor slab planned. Floor covering 65mm Screed UFH Pipwork 150mm PIR insulation 100mm c35 concrete with mesh Whilst looking at the overall prices of each piece of work there's a couple of questions that have come up would it beneficial to change the floor structure to incorporate circa 250mm of eps insulation under the concrete slab, instead of the 150mm pir above slab. And whilst I am at it, possible to incorporate the Under floor heating pipework into the slab, as opposed to having the pipework in a screed on top of the slab? The reason for looking at this is to save time and money. The 250mm of eps insulation has similar u value to 150mm pir, whilst being cheaper - circa 1k at the moment, but there is another price increase on pir due in February. If I incorporated the pipework into the slab, I could save circa 4k for the screed work post panel installation, but it would also mean I could crack on with the studwork immediately after the kit erection as opposed to laying pipework and ordering in self levelling screed. any thoughts/drawbacks?
  8. Hi all, Trying to figure out the best option for ufh in our new extention incorporating existing kitchen area etc. (I’ll attach the plans) I can’t figure out, A: is it best to clip onto foilbacked board in between joist and biscuit screed/cover with chipboard? B: lay routed panel boards and tile straight on top? I don’t really like the idea of tiling straight on top of the pipe as In “B” but will I feel the benefit and will we get enough heat from option “A”? the boiler is going into the utility, would like two zones, one for the main living space/kitchen and the other for the shower room. it’s a mine field, any help and guidance would be much appreciated. Also any other systems/options that would work? Best, Keith. GROUND FLOOR.pdf STRUCTURE 1.pdf
  9. 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=""><img src="" alt="UFH-current" border="0"></a>" /> Issue The 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=""><img src="" alt="UFH-options" border="0"></a>" />
  10. I want to lay underfloor heating but also create a firm feel underfoot that doesn’t transfer footstep impact sound below. TorBoard RdB looks like it might be the perfect answer, though it’s pricy. Does anybody have experience with this ufh board product?
  11. Converting a 3 bed very dilapidated 1930s semi into a 4.5 bed modern home. EVERYTHING is being gutted except the joists. Quotes are way over budget, particularly for the underfloor heating. I had specified wet underfloor heating throughout all three floors of the house (ground = 800 sqft, first = 750 sq ft and loft = 450 sqft), with the ground being imbedded into screed and the first and second floors being laid within some high performance extruded polystyrene boards made by Cellecta called XFLO. XFLO is quite expensive, about £26 a square metre, but the reason I had specified them is that they provide good insulation to make sure the heat goes up, are CNC drilled by Cellecta to meet any pipe layout requirements we specify and also feel quite firm underfoot. The other advantage of the XFLO is that you can lay the finished floor directly onto it. Underneath those XFLO boards, I had specified a 6mm dense rubber matting (which comes as a 10m by 1m rolled product, so pretty easy and quick to lay) to absorb impact sound, and underneath that 18mm tongue and groove ply which is nailed directly onto the joists (whereas the rubber and XFLO are just floating). In between the joists I was going to have mineral wool to mute airborne sound travel, and underneath the joists I was going to have the ceiling attached using resilient bars (with market name "Genie clips") to isolate the ceiling from the joists to further prevent sound transmission. The whole system is to be zoned as 9 zones, including one zone for the 3 towel radiators (which will be the only radiators in the house, one for each bathroom), although I'm going to provide Tado thermostats, one for each of the 8 UFH zones and a Tado smart valve for each of the towel radiators. One builder has quoted about £25k plus VAT for all of the above, and the other about £28k plus VAT. These quotes don't include the thermostats (I'm providing those). When I have challenged each of them on why this is so expensive (I was expecting about half the cost) they have said different things. The first builder has said that I could save £2,500 to £3,000 money by losing UFH in the loft and in most of the first floor, and instead having radiators there. The second builder doesn't agree that would save any money and is also trying to respect our reasons for having UFH. Instead he just thinks the system I've specified for the first and second floor is overkill and that I could make two changes which would save about £4k in labour: First, instead of 18mm ply plus 6mm rubber matting plus the XFLO boards (which are about 28mm thick) I should just lay a product sold by theunderfloorheating store calledProWarm ProFloor 22mm pre-routed chipboard. I've looked this up and I see the benefit. Like the XFLO boards, you attach it directly to the joists and it comes routed (though with standard not bespoke routing) and enables you to fix the finished floor directly. It costs roughly the same as the XLFO, but it saves the builder the trouble of having to lay the rubber matting and the ply, so the saving is in the cost of the matting (£6 per sq metre), the ply (about £14 a sq metre) and the labour to fit those two layers. Second, he says that in the bathrooms, I should just lay electric UFH rather than wet. He accepts it's dearer to run, but he says I can have smart timers on it to make sure I only have it on when needed and as there will be wet towel rails in there, I really won't use it that often. I think I'm willing to accept his second point and fir the electric UFH in the bathrooms, but I'm concerned about the disadvantages of the first point, which I see as follows: 1) I lose the impact sound protection provided by the 6mm rubber - is this such a big deal given I have an isolated ceiling and the mineral wool between the joists? If so, can anyone think of a way of combining a fairly cheap but effective sound impact layer with the 22mm pre-routed chipboard? It would only ever be my kids running around, so impact sound is not a major issue, but I want some protection. 2) Chipboard is not as durable or as strong as ply. Although both will feel similar at the outset of their lifespan, what will they feel like in 12 years time? I plan to be at the property for 12 years at least, but hopefully longer and I don't like springy floors. 3) no bespoke pipe channels like Cellecta offer with XFLO. But is this overkill? Maybe I don't need bespoke pipe layouts. Builder says that the 22mm pre-routed chipboard just has channels at 200mm pipe centres and that is a standard construction for first and second floors. Although most of the rear of the house is being extended, so it will have insulated cavity walls, and the loft will also be well insulated, the rest of the house has no cavity walls. Keen to hear your thoughts on the above. Thanks for your time!!!
  12. I have finally come to the conclusion that we are going to fit an ASHP and cylinder to our property. Over the years we have been drawn to the Sunamp, Sunamp and Willis heater courtesy of @TerryE but with the recent problems encountered and the uncertainty of how the system works if/when you have a problem does not appeal to us (Apologise to all those Sunamp owners out there). So having chosen ASHP it brings with it the problem of designing/installing the system and even though I have plumbed houses and fitted central heating systems the thought of this seems quite daunting.I have never fitted a cylinder before so this in itself is new territory so I am appealing to people who have done this themselves @joe90 , @ProDavefor any guidance you can pass on to me and may be some more help from @Nickfromwales and @PeterWif you can spare the time. I am struggling to get anybody locally who can just fit this low KW ASHP with cylinder without wanting to double the capacity, have it interact with the space station for telemetry and spend a whole week on fancy control systems. I have looked at the plug n play systems from the likes of LG and Samsung which would be very easy (ish ) to set up but would cost quite a bit more. I know I need an inverter in the ASHP and a blending valve(!) now so you can see I need quite a bit of advice to be able to understand the system and what I require. The house is Passive so will be minimum heating and I intend to keep the DHW temp low like Joe and Dave so I am trying to give you as much info to help with your advice hopefully. I know people have bought their cylinders from Telford but not sure what cylinder to buy? We will be doing solar PV at some point just not sure when. @joe90has mentioned having a buffer tank but he is not sure whether he actually needed it although he has his immersion in this tank I know you can have an immersion in the main cylinder and if I had a Willis heater as an immersion heater this could double up as a stand by if I ever have ASHP problems but how does this all connect together!! Hope you understand my dilemma and hope you can help me design and understand my DHW and UFH system from the start to the finish!!
  13. To those who commented on our GRP, this is not an update. The next installment to that will hopefully be at the end of next week when the crap roof will be off and a proper company coming in to sort after we insisted on an insurance backed guarantee. I shall update then, watch this space! Flat roof aside..... All our new extension had insulation laid and our existing flooring excavated for insulation too. We had the UFH pipes laid and there was A LOT. And then screed laid which is suprisingly even and flat using TG Cemfloor – a liquid self-levelling screed. Needless to say they did a better job of this than the roof. And part of the in roof solar frames have also gone up. Our builders found these up the loft when taking down the old ceilings. Unfortunately empty! Someone had a good party 😉
  14. Good evening all, I was after some advice please. We have an underfloor heating system installed with 8 zones. We are finding it takes quite a long time to heat under on certain zones. What operating pressure should the system be at? Ours is currently set to 2 bar? We are finding that front room is colder than the other rooms, the UFH is installed under floorboards in the insulation boards supplied, ontop of the floorboards we have tiles and wooden flooring. Is this right? Will the heat travel through this many layers? This is what was recommended at the time? Also what should the pump setting be set at? There are serval settings which can be selected from the front of the valve? Without leaving the UFH on all day being controlled by the thermostats it does take quite a long time to heat up? I’ll forward on the plans and the photos of you could get back to me that would be great? Cheers Ash.
  15. Hi, We have recently had wet UFH installed by a professional - three loops, but acting as a single zone with a single thermometer. We noticed that the flow meters showed no flow and despite the thermostat being set to 30'C, the floor didn't seem to heat evenly or as hot as we would have expected. Apologies I have little plumbing experience however started researching and I have some concerns over how it's been plumbed in. I had understood that a UFH manifest should have a flow block and a return block. I presume water should be pumped from the flow block (where the flow meters are) through the UFH underfloor piping and back to the return block where the actuators are. Therefore I assume that normally the pipes connected to the flow block should be warmer than the return pipes. In our set up, we normally see the opposite - the return end of the pipes get hot first and stay hotter than the flow end of the pipes. Also weirdly, if we turn the mixer thermostat to as hot as it will go, and then turn the pump to minimum, we see flow registered. If we increase the pump speed, the flow registered by. the flow meters decreases So it feels to me that something or several things are reversed and that we're actually pumping water the wrong way round (would flow meters register a reverse flow?). In other google images of similar setups, I see the output of the mixer plumbed into the flow block, whereas ours is plumbed into the pump which is then plumbed into the return block. I would be really grateful if someone could look at the attached photos and let me know your thoughts - am I right that the flow is reversed and is there any reason why the plumber would have done this (he's not replying to our messages at the moment which also concerns me!). Thanks in advance
  16. Trying to get my head around what I need to install UFH and four towel radiators and three small aluminium panel radiators. Been in touch with Wunda, asked about Wilo pumps and they said no longer supply, asked about a lower temp range blending valve and they said 35 is the min. So I started looking around at other suppliers. Came across Emmetti, and they do a mixed rail manifold M3V that has a hot side for rads and a cool side for UFH. Or is this just overcomplicating matters. Has anyone used their weather comp controls? They have a modulating blending valve connected to their weather comp, as I am feeding all the heating from a buffer tank, I presume I cannot weather comp the boiler, as it only gets a call for heat from the buffer stat, or the DHW stat in the main tank. My UFH is sitting in 55mm Cemfloor screed, sat on top of a concrete beam and block floor, with 300mm sprayed insulation on the underside, so it will be slow to respond. I was originally looking at Heatmiser Neo stats and multiple zones, but now thinking that due to the slow response, that the whole ground floor, circa 100m2 will eventually even out temp wise, and may be better controlled via weather comp and the modulating mixer valve. Has anyone any real life experience of this set up? It's a big learning curve for us, our project has gone from an estimate of six months to over 18 months in now, and we are keen to get the floor screeds in and heating going before winter. thanks Andy
  17. After much heart ache, time and tears I'm looking for some advice from you guys regarding my heating system, which is completely separate from DHW. I plan to directly heat my slab with ASHP using Willis heaters as back up. Hydraulically does this look ok? Input much appreciated.
  18. I have cemfloor floor screed with ufh, it doesn't appear to give off much dust. We are hoping to move in shortly with lots of uncovered floor and I don't want extra dust. What can I seal the floor with that won't be detrimental to future tiling or wooden flooring being laid? I have been told to avoid the traditional PVA as it will crack and peel off with ufh, not sure if this is true. Thanks in advance, can't actually believe I have just typed the words "move in shortly"
  19. So I have stripped out all the existing pipework, back to the incoming main, on my major renovation extension. I have an overall concept of what I am trying to do gleaned from reading this forum, but have many questions! Trying to make sure I am on the right track before buying all the kit. I have three bedrooms all with ensuite WC, basin and shower, one has a bath. Heating is UFH on ground and lower ground floor, radiator in each bedroom, and towel rail/radiator in each ensuite/bathroom. Downstairs also has a bathroom with shower, WC, basin. I have mains gas. so the concept is to have a new gas system boiler, an unvented cylinder and run UFH, heating and hot water, all from the tank. Is this how it works? The tank I am looking at is from AVC, and is a tank in tank system, so using the primary heating water as a buffer for the UFH and radiators. Using Hep20 from a manifold for hot and cold water, and run the upstairs radiators from another manifold upstairs. I know I need a double check valve and stop cock on the incoming main, and a PRV before the tank, the tank comes with a mixer valve. After that I am not sure what I need I have seen some on here use one large, valved, brass Hep20 manifold say in the utility room next to the boiler and tank, to feed everything, others have used sub manifolds for each room, using the much cheaper, plastic, non valved Hep20 manifolds. Is this purely to save money, I like the idea of being able to turn off individual consumers from the manifold, but unsure in real life how often this could happen, cost difference is considerable, but then it is a one off cost. Control wise I am planning on using Heatmiser Neo thermostats on each zone, and a Neohub and their wiring centre for the UFH and also for the radiator manifold circuits. Boiler was looking at Veissman Vitodan 200 series but unsure on sizing, these are available with weather compensation, but will this work with Heatmiser, how do they talk to each other? Was trying to find modulating thermostats but Heatmiser don't offer them. Also unsure on UVC sizing, as it appears I could run a smaller tank, 210 litres, if I have a large enough output boiler to reheat it fast enough, or is it better to have a larger tank, 300 litres and a smaller boiler, also have a solar array of 3.7KW so was hoping to use a diverter to an immersion in the tank for all excess solar. I apologise for so many questions, but feeling a bit overwhelmed by everything.
  20. Grateful for advice on the following. I'm doing a self build in the Stirling area. Its a five bed property (180m2 in total) with ufh downstairs (120m2) including three bedrooms downstairs and two bedrooms upstairs with rads. One bathroom and three en-suites in total. I was hoping for some advice on boiler and UVC sizing? We will be required to install PVs so I'm also wondering what issues to consider in terms of integrating it with the heating system/hot water? Looking for the most cost effective option. I did consider ASHP but have decided to opt for LPG and PVs. Any pointers much appreciated.
  21. After various delays, the time has come to get some heat into the house, and as there have been a few on BH that have gone down the route of Willis, thought I would give it a go as well. Hopefully others will find the blog entry also. Background: Renovated (3G passiv-rated windows, 120mm EPS EWI, 400mm loft insul, MVHR - not tested air leakiness yet) / extended (175mm SIPs) south facing detached house, East Kent 156sqm of wet UFH in 100mm concrete (with circa 300-375mm EPS insulation) 130L in UFH Wunda 12 port manifold (The heating valve on the manifold operates in the range of 30-70oC) Wunda wired room thermostats for each room (but probably won't use for this temporary setup now) 12Kw eDual for DHW (not to be included as part of Willis setup) 12Kw Sunamp for DHW/UFH (not to be included as part of Willis setup) 3.8Kw PV (potentially have further DIY grid implemented later on) Not looking to cater for worst case low temps as at these times will just plug in some extra heaters: I originally ordered 2x 12Kw heat batteries for DHW and UFH. Total reliance on the PV in summer and then off-peak grid in the winter. An all electric approach initially without ASHP. Not keen to spend £8-10k on an MCS installed heat pump to get back an estimated / possible £8-10k. Installers seem very vague on the RHI returns and if I have read correctly, I will have to be metered in order to qualify in any case (as have not lived in the property previously). Since the house will be far above buildreg stds (but below PH level), I simply won't be using the amount of expected input that the installers calculate - hence I won't be getting back the cost of the ASHP supply and fit install. So most likely won't go down the MCS route, and if I were to install an ASHP, it would be a cheapy from fleabay. Having excluded using an ASHP, I learnt that Sunamp were testing various units late 2019. But typically with Sunamp, after continued confusion on their part as to what ASHPs they may have tested/not tested/will be testing soon, I've made the decision that I can't want any longer on their input. So for now I will leave the ASHP option until later on and perhaps consider a propane unit (e.g. Vaillant ) when they come online on a non-RHI basis if I can get a decent install cost. Willis Heater approach So therefore looking to heat the UFH with 2x 3Kw willis heaters in order to progress with the internal house work. Thought I'd add some info on here as a lot of people like myself aren't familiar what they are. They originated out of Ireland and still much in use over there. They're essentially external immersion coils and instead of sitting inside a tank are simple external electric units - AKA "Willis jacket", "standard sleeved immersion heater"," inline electric heater". Googling should get you something like this: Item Weight 1.15 Kg Product Dimensions 30 x 9 x 9 cm I have tried to get plumbers interested in rigging this up, but they're either not interested or have told me it's not possible/don;t know what a willis heater is. I've managed to plumb in all the Hep2o in the house, so hopefully this won't be too much of a bodge. @TerryE has kindly discussed his set up which is pretty impressive with his DS18B20s set into the walls etc. I'm no programmer and my javscript is mainly simple web stuff and wanting to get heat into the place ASAP, I just want a KISS approach for now. Perhaps later I will think about having some of it programmed using Terry's Node Red option which makes for interesting possibilities. Get a feel for Terry's approach here: But as I've said, I'm after a bog standard dummies approach to this - seriously KISS: So rather than wiring up room thermostats to the wiring centre, I will for now simply use the Willis inbuilt thermostat and set that to gradual increasing temps from 10oC up to a max of 25oC. A gradual heat increase seems safer in my mind. My only concern is if the Willis thermostat fails and carries on beyond 25oC - up to max temp. Obviously I will have the manifold mixing/blending valve that should restrict temp flow into the UFH also, but is there a further failsafe to consider? Dummies layout. Eventual Sunamp units (for DHW) will be located on left of manifold so having to locate Willis heaters to right and expansion vessel top right: FYI: The immersions need to be turned the other way (so colder water enters the side) Parts list: 15mm copper pipe. The Willis heaters are 15mm so I presume plumbing them into the manifold with 15mm would be okay? 15mm plastic pipe for cold return should suffice I presume? Bottle vents - automatically release any trapped air (like this one). Do I need any and if so where do I place them? Willis heater (ebay has the cheapest) Expansion vessel - 8litres sufficient for total UFH volume of 130L? (like this one) 20A DP switch outlet (for each willis) from a 16A MCB (like this one) . Probably one for each willis Immersion timer (like this one) to be added possibly when I change over to E7 low tarriff rates Will get an electrician to wire it all in for me! Be grateful for comments, suggestions and any answers to above questions! FYI: I'm no way the first person to install a Willis, so here's a list of other users on BH that have gone the Willis way and will know more than I do: @dpmiller: photo / details here @TerryE @vivienz @CC45 @chrisb here @Gav_P - here (Any pics?) Willis instructions: schematic
  22. Hi I've just joined the forum. I live in Southport Merseyside. My main hobbies are Digital Photography & Formula 1. (watching). Back in November 2019 we moved into a 5 year old apartment with water based UFH. From day 1 we experience problems with pressure loss from the Worcester Bosch Greenstar 32 compact boiler, constant running of the system at night, 4 visits from WB claiming there was nothing wrong with the boiler, yet twice they re-pressurised the expansion tank, replaced it & the PRV. The system has a mixture Heatmiser & Maincor components, 2 of each thermostats, Maincor Programmer, Heatmiser UH3 wiring centre. In my working life I was a Project Manager for a refrigeration cabinet manufacturer, handling projects for national end users such as M&S, Morrisons, Asda, Macdonalds, the list goes on, I'm leading up to saying I do know something about air conditioning heating & ventilation. I think that's enough abut me, back to the problem with the apartment. Following numerous visits by the agent, his plumber, electrician & WB, the agent is trying to persuade me to set the boiler outlet temperature above 65C, which it has been set at since we moved in. Set the thermostats on the "set back" position on the 3 position switch. Having scoured the'net I discovered BS EN 1264 which reading between the lines says that Water based UFH systems with screed covered pipes should not exceed 65C at the boiler outlet, 5C lower in the EU version. Can anyone confirm what I think or throw any light on the necessity to increase boiler outlet temperatures over 65C Thank you in anticipation.
  23. I am a fan of flexibility, having options, and for simplicity. When I build my new house I plan to include the wiring and pipes for both an ASHP and gas boiler. To go with the ASHP, I will also include UFH piping in my reinforced concrete raft foundation. Installing all the options at the time of the build costs peanuts. But how about adding one more cheap option: from a capital cost perspective, the cheapest of all. When I pour my my raft foundation, why don't I also include some electrical heating wire too embedded deep within the concrete? From checking on eBay, the cost of loose heating wire seems to be about £150 for 2kW. £150 really is peanuts! And it beats even a Willis heater for simplicity. Wet UFH after all needs a manifold, a pump, regulators, etc. While I would still have all the other options available later, I could use the wire heating for the first couple of years while I learn how my new house responds. What does everyone think? Bad idea?
  24. We have wet UFH (in the bathrooms) in a Passive house and wonder whether I need electric UFH in the two downstairs bathrooms? Reason being we will probably do the chunk of the wet UFH in the night if we go down the Willis heater route so there will be no form of drying the floor when we shower although I have no experience of how the slab will work when we eventually get in!! The showers are wet room type and measure 1.9m x 0.9m with a glass screen measuring 1.3m wide and 2.0m high but I fear we will have water getting outside the wet zone and do I need to be thinking of drying it by some other means? We obviously have MVHR so not so sure how effective this will be at drying out the rooms but do people think it is worth putting an electric mat in place? TIA
  25. My upper floor, that is. Due to the vast number of MBC guys on site early last week, my upstairs was ready for the underfloor heating pipes and spreader plates to go in much earlier than my plumber had anticipated so the plates were duly put in. MBC were due back on site this morning to get the egger boards down on the first floor, so it was a case of then or never. The downstairs UFH pipes are embedded into the concrete slab and so a different method is needed for the upstairs, and this is it. What you are looking at are aluminium spreader plates with the UFH pipe bedded into them. The spreader plates are thin sheets of aluminium with two semi-circular recesses running the length of the plates. These are stapled to the joists along their length and their job is to hold the pipe in place and also to diffuse the heat over their area. The plates are very thin, barely a couple of mm thick, I would say, and very sharp, as I found out when poking the corner of them all stacked up in the shrink wrap packaging when they first arrived. Here's what they look like individually: There were a couple of delays in getting started on Friday and as a consequence work went on till well into the evening. UFH by sunset: After some hard graft on Saturday, it was all in place and the manifold had been attached, pressurised and tested and all looks good. Once all the egger boards are on, the centres of the spreader plates should be stapled along their lengths to the boards above to ensure good contact and heat transfer, although this was overlooked and not done but not picked up on in time to be rectified before the flooring went down on top. I did not sit idly by whilst all this effort was going on, oh no, not me. I had some very important decisions to make and these took a high level of innovation and imagination. Like, where's the best spot for the furniture in the to-be living room and where do I prefer the view? Really important. And, it turns out, that off-cuts of EPS upstand make for a really good improvised sofa. To be seen in all the best furniture showrooms soon: Having tried this, I came to a very meaningful conclusion. I need more furniture. Another thing for another day. Back to business, MBC were back on site today, a team of 4 to put the egger boards in place. You can see from the spreader plate pictures above that there is virtually no joist exposed, hence the need for screwing them down, particularly as the spreader plates will need to be attached from them underneath. The guys also used the egger adhesive along the tongue and groove runs of the board sides. Being a complete ingenue when it comes to all matters of construction, I was pondering last week what the purpose was of the hefty blocks of wood set into the recesses of the I shaped steels. Today, I found out. The posi-joists don't just rest in place, they are very firmly attached using steel thingies called roof hangers. These are they: And this is where they go: On other matters, I'm busily chasing down roofers at the moment, and they are proving difficult to get hold of. One has already declined to quote because they are so busy, but I'm working through a list of possibles, so it will get done. I've also booked in for my service alteration on the electricity - it's on a pole via an overhead line right now but will be buried eventually and the pole removed. Current date for this is 17th October, but electricity companies dance to the beat of their own drum so this could easily change. It's the big stuff back tomorrow with the final frame delivery and the upper floor being constructed. Sit tight for the next thrilling episode!