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  1. 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?
  2. 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
  3. 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>" />
  4. 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.
  5. 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
  6. Hi, i am trying to determine a method to accurately measure the depth of applied floor screed to a new build. i did not apply it, but it appears to be thin in certain spots i.e. not to the required depth.
  7. I need advice on the best material to lay ontop of wet underfloor heating between existing joists to lay engineered parquet flooring. Floor construction is made up of suspended timber floor with battons to support 70mm insulation board. UFH heating pipes then clipped to insulation and covered with 8:1 pug mix. My supplier of the engineered flooring (which is 15mm thick) recommended screw ply onto joists and then glue engineered flooring onto the ply, however I am worried that this will have a detrimental effect on the heating efficiency. Is there a better option to this or does it sound like the best option? And if so what thickness ply would be recommended? Thanks
  8. Hi all please can someone tell me if you have a Heatmiser Neov2 how long does it take to heat a kitchen up when you have this system installed. My kitchen is like an ice box... I have left the heating on overnight but it simply isn't toasty in there at all. Any pointers would be gladly welcomed. Jay
  9. Hi I've recently purchased a 1bed "colony" house in Edinburgh. For those unfamiliar with colony houses, these were homes built throughout Victorian Edinburgh and were designed as homes for the skilled working class, more details about them here if you are interested. Mine is a 1 bed ground floor, 45sqm altogether, with a small front and back garden. It's currently fitted with electric storage heating that I am hoping to remove and replace with a small air source heat pump and install underfloor heating throughout. I found this forum through my ASHP researching and have found it really useful so far. I also want to change the internal layout, so the largest rooms are for the kitchen and living room. I wish to move the bathroom to the opposite side of the house and turn the current kitchen (small, narrow) to a very small double bedroom! This requires a couple of walls knocking down and rebuilt. I won't have the keys to the property until late November so works can't start yet but I'm trying to do as much research before then. Thanks all, looking forward to asking lots of questions as I have them...!
  10. Is there anyone who can help me with information about thermal expansion cracking of the slab or walls in a passive house? I have a technical concern regarding passive raft foundation and (ICF) concrete walls for a passive basement construction (part of a passive dwelling). In technical terms: Any solution to accommodate anticipated differential movement between the raft foundation concrete with an underfloor heating system and the concrete walls that sits on the raft foundation? My concern is regarding the thermal expansion of the concrete in a raft foundation with an underfloor heating system. The temperature of the concrete in the passive raft foundation may fluctuate with 8°C / 15°F or more, compared to the temperature of the ICF concrete basement wall, depending on the season and the heat from the underfloor heating system. With the size of the raft foundation plat, this will induce a calculated expansion of the foundation slab concrete with 2-3 mm. The ICF concrete walls, supported by the foundation system, does not expand, as the temperature do not fluctuate similar. Perhaps we should made expansion joints between the raft foundation plate and the ICF wall, allowing them to slide the anticipated 2-3 mm on each other? However, to make the basement construction strong, we would want to connect the raft foundation system concrete and the ICF concrete wall with reinforced steel. Have anyone heard of this problem and any solution or guidance on how to solve it? Are there any experience about this potential problem anywhere? Expansion cracks in a concrete slab can potentially damage technical installations in the slab, including the heating pipes in the floor/foundation plate. I would very much appreciate any tips / advice. :-)
  11. Hi everyone. New to the group and was hoping for some advise. I have a JG underfloor heating system installed under my kitchen and through to a downstairs toilet where the pump and manifold are fitted. In the loft above the toilet run the 25mm flow and return direct from the boiler. Can I tee into these to supply the ufh? I have a cable run in from this (ufh thermostat)to the controller in the airing cupboard which I was hoping to link across the heating switch?? Sorry if this is vague or my terminology is not very good. Any advise appreciated. Thanks in advance
  12. Hi everyone. New to the group and was hoping for some advise. I have a JG underfloor heating system installed under my kitchen and through to a downstairs toilet where the pump and manifold are fitted. In the loft above the toilet run the 25mm flow and return direct from the boiler. Can I tee into these to supply the ufh? I have a cable run in from this (ufh thermostat)to the controller in the airing cupboard which I was hoping to link across the heating switch?? Sorry if this is vague or my terminology is not very good. Any advise appreciated. Thanks in advance
  13. 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.
  14. I introduced myself about a month ago under the heading New Summerhouse. I had some interesting exchanges on solar panels to power underfloor heating in the summerhouse. I have now rejected this option in favour of a north-facing sloping roof (thus getting 3 metres of height at the south-facing patio-door-lined side) with no solar panels, and powering the underfllor heating from the mains. I've been to B&Q and looked at the sheets of underfloor-heating insulation sold there, which seem to be pink poystyrene 1 cm thick with a grey coating to each face. Is there a more eco-friendly alternative, perhaps on the lines of the shredded-paper insulation available for lofts. Perhaps not, as anything underfloor will get walked on/compacted and lose insulting capabilities. Fran
  15. The Homelux Heatwave insulation board I saw on display in my local DIY store appears to have a core of pink polystyrene (1 centimetre thick) with a grey (fire-retardant?) skin to each face. Is there a more eco-friendly alternative, along the lines of shredded newspaper insulation? If so, would this need to be thicker than 1 centimetre? Fran
  16. I've been wrestling with Loopcad for sometime now and am loosing the will to live. I take 1 step forward only to follow it with 2 steps back!! Are there any kind souls out there who are proficient in using Loopcad who could help with my loop design for the ground floor and save me from tearing the rest of my hair out? I'm trying to use spiral counter-flow where possible. Here are 2 versions of the GF plan, one with dimensions and one without.
  17. I only got to use my UFH for a month at the beginning of the year when @Nickfromwales and @PeterW fixed it for me as it's been switched off for summer ever since. Now that I've switched it back on in 2 rooms I thought I had better try to understand how it operates a bit more. So first questions: On the TS there are 2 cylinder stats. The top one is set to 65C and the bottom one to 45C. When a room calls for heat what determines whether the boiler switches on? The bottom cylinder stat at 45C? And when it gets to 45C the boiler switches off? And if the hot water is switched on I assume the boiler will stay on until the top cylinder stat is at 65C or the time stops? So the cylinder stats are for different purposes and work independently? Last night it took a fair while for the temp to rise from 17C to 20C and the boiler kicked out 37kw over the course of last night and first thing this morning. Maybe I should have expected this the first time the slab has had to heat up this year however .... This morning when I got up it was at 20C and it hasn't dropped at all today so the heating hasn't come on yet tonight which is a good thing I guess. It hasn't been baltic outside today however. Will be interesting to see how much it drops when it's colder.
  18. Hi all, about to embark on self-build project. We have plot and planning. The layout optimises solar gain so I am keen to achieve passive house standard. I have noticed on this forum that many self-builders seem to include UFH in their passive house build but I have been told this is simply not necessary... So i'd be grateful for thoughts on this please!
  19. Apologies if this has been asked before but I'm looking to install UFH upstairs on a new build. There seems to be a million dry and screed options. Can anyone recommend the best / cheapest system to go on posi joists?
  20. My thoughts, all along, have been to have wet underfloor heating throughout. Reading another thread, can't remember whose, has made me want to think about it a bit more. I will be living there alone and don't intend to move until I have to be carried out. (Hopefully in a box as the thought of .... no I'll not go there) House will be well insulated to modern standards BUT not passive by any means (didn't find this forum early enough) Options I am currently considering Wet underfloor heating and hot water coming from a combi Wet underfloor on the ground floor, electric elsewhere rarely used except in dressing room (I like a cold bedroom and other rooms won't be used that often) All electric including immersion heater for showers All electric with electric showers and instant hot water features to sinks Experiences, pros, cons or alternatives to consider please. Added floor plans for info with downstairs loo added and bathroom to become just a mini en suite off second bedroom. (Second bedroom and ensuite will get 3 to 6 days use a year)