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Found 71 results

  1. Just wondered if anyone has experience of running an ASHP using the cheaper rate economy 7 tariff and whether it makes any real difference in running costs. I seem to remember that you have to pay a slightly higher day rate if you have E7, and that, coupled with the fact that the ASHP would be running at night when it might be cheaper but also colder would seem to maybe cancel any financial benefit. Also, it seems that running an ASHP 24/7 makes better sense and it's unlikely to be able to run an ASHP on normal rate during the day and E7 at night. Thanks in advance to anyone who can shed some light on my ignorance!
  2. I am in the process of building a Passivhaus. As there is no gas, I will be using an ASHP for Heating and Hot Water. Heating will be via radiators located downstairs and upstairs. I am in the process of deciding between two Mitsubishi heat pumps - the 4KW QUHZ (CO2) which is matched with a Thermal store and the 5kw PUHZ which is matched with a Hot water cylinder. I have phoned up Mitsubishi and spoken to them about the QUHZ (CO2 air source heat pump). There is no additional maintenance required for the QUHZ. I also asked them about reliability and there view was that as they've had to increase the spec of the QUHZ in several areas to take into account that CO2 is the refrigerant so they expected the QUHZ to be as reliable or more reliable than the PUHZ. I think there is a big difference in the way that it heats up the water as the QUHZ uses a thermal store rather than a hot water cylinder used by the PUHZ. Not an expert in this area, but research I have carried out suggests thermal stores are less complex than hot water cylinders. Idiots guide from Mitsubishi was to use the QUHZ if your hot water energy requirement exceeds your energy requirement. Using the more detailed data for range of temperatures supplied by Mitsubishi the services engineer checked performance in PHPP for specific loads and temperatures for our house. It indicated that the heating is indeed slightly better with the standard unit but hot water is considerably better with the QUHZ which correlates with the feedback from Mitsubishi. These were both modeled at 45 C heating design flow temp and 55 C DHW supply temp. So on the surface it would appear the QUHZ is better suited to my needs. The only caveat is that it is a relatively new technology for Mitsubishi (introduced 3 years ago) and I think in the market place in general. I had an early condensing boiler fitted to my current self build and it was always breaking down, so I am a little cautious of using anything new on the market because of that experience. Heat pumps seem to be tried and tested technology however so maybe I am worrying unnecessarily. I would welcome any thoughts / feedback on this.
  3. A couple of years ago, I bought a house heated by a 14kw Ecodan ASHP with a Mitsubishi pre-plumbed cylinder system, that was installed in 2015. It has zone 1 to heat 10 radiators and zone 2 to heat 3 loop wet UFH for the kitchen and utility - also heats DHW. During the colder winter months and late frosts this year, it was clear that the UFH was failing to heat the kitchen/utility floor. The input to zone 1 is physically higher on the low loss header, so if both zone 1 and zone 2 are on at the same time, zone 1 takes the heat, and no heat travels down the low loss header to zone 2. If just zone 2 is on, some heat goes into the zone 2, but much of it travels down the low loss header to the return. This causes the return to be almost as hot as the flow, so the Melcloud reports show the return temperature tracking the flow temperature. When it reaches the peak temperature, it cuts out and flushes with cold water from zone 1. This shows as a sawtooth effect of fast cycling - the cycling is very regular, every 10 minutes. If zone 1 is on by itself, this does not happen - the return remains lower than the flow and there is no cycling (I've attached a melcloud report showing this). The system has been serviced, I've flushed the UFH loops out (via hose - a small amount of muck came out but not much and the flow was OK) and inserted more biocide. I've tried altering the pump speeds. To reduce any flow obstructions, I've removed the flow meters and used blanking plates. I've replaced the Heatmiser UH2 with a standard Ecodan wireless thermostat, and Salus THB23030 actuators. I still have the 10 minute cycling. I have a feeling that the ASHP is too big for the UFH by itself - but not big enough to heat both zone 1 and zone 2 together. I've tried asking UFH and ASHP installers and maintainers, but they look even more baffled than I do and offer no help (with all the green deal stuff, they are too busy installing new systems to bother with maintaining existing ones). I just wondered if anyone had any thoughts or ideas as to anything I could try? Many thanks Eric
  4. After many years running a combi gas boiler we took the plunge and replaced with an LG R32 7kWh air source heat pump. The system has now been in for 3 weeks (today in fact). We reported an issue to the installer over a week ago that it seems we are running out of hot water quickly. Understanding this is no longer instant hot water and we are not going to be mixing with cold as much I did some measurements... Hoping someone can shed some light if this is an issue or we are expecting too much from the system as we have only ever owned gas combi boilers in the past. Before someone showered I read off the controller the temperatures shown DHW = 47 Water IN = 22 Water OUT = 22 (The DHW is set to 55C) Shower is a digital Mira platinum set to 35C. We use the ECO setting and measured the flow with a jug and a stopwatch over 1 min = 6 ltrs of water outputted. Shower was ran for 20 mins, by which time the water was noticeably cooler, to the point it was not comfortable to shower. Controller temperatures DHW = 33 Water IN = 36 Water OUT = 43 The installers fitted a 210ltr unvented tank. This was sized based on our property - 3 bed. So this one shower used a total of 120 ltrs of water (some of that mixed with cold). For those that monitor the water temps do you see a drop like this or is our system not kicking in soon enough to maintain the heat in the tank?
  5. I'm installing a 16kw air source heat pump next week, and need to put in a spot to anchor it. I'm wondering if people can comment on how they've installed them and what has worked? I'm aware this ASHP will put off a lot of water (60-100l a day) and there's an inlet for sewer/waste water (it's a combined one system) about 4ft away from the installation point I've chosen. Should I put down some combination of sand, gravel and top off with cement? Or just small cement bits for the footings for the ASHP mount points? And what about water drainage? I can run some 40mm pipe from top of the pad, or a kind of soakaway. I'm just not quite sure whether 100l is too much to just drain in place. The ASHP is downslope slightly from the sewer inlet which is only about 2" below ground, so it's likely I'd need to run pipes above ground from ASHP. Would love to hear what you've done, and what has worked - and photos if you have 'em!
  6. Afternoon, I wasn't sure if this should go in the renewable section or Scotland section. I was just wondering if there was anyone on here from Aberdeenshire or the surrounding area who has had an ASHP installed. Can you tell me who you used and your experience of the company/installer? Thanks Paul
  7. Does anybody have any experience of ASHP from Cool Energy? I became aware of them last week when I visited the Sunamp factory and after looking at the Cool Energy site they seem to be considerably cheaper than a lot of their competitors. I was told at the time that they were not accredited by a scheme that allows you to claim RHI but as it is likely to be included in a smallish house I don't think the RHI payments would amount to much. I know very little about ASHPs so do they vary in performance and efficiency and if so do the Cool Energy units compare favourably and are they reliable? Any advice or recommendations welcome.
  8. I understand that flow rates are affected by lots of variables like pipe size and type, bends, elbows, joints and so on and that it is a complex calculation to work out the head size to get the correct pump to achieve a desired flow. The issue I have is a bit odd as my head was calculated at around 8 metres. pump then recommended was a Grundfos magna3 25 - 120 on its curve it’s is capable of 3m3/h on 11m head. it’s maximums are 9m3/h and 12m head. However I am only getting around 2m3/h and the pump is telling me I have a 12.9 metre head. the pump is set to constant curve at 100% running as an uncontrolled pump at its maximum. I have e tried all of the settings and on anything but Max get a low flow reading. the loop is described as follows starting heat source flow. 22KWH dream ASHP (needs 3.2m3/h flow rate) outlet to 22mm copper. up to attic 3m in 22mm copper. through the attic to the storage tank approx 30M 22mm copper, 2 engineered bends, 5 elbows. Down 2m into 1 elbow. Plus elbow on entry to the tank. Telford tempest 309L tank (this has 30m 32mm coils. this then runs back up and through the attic back to the ASHP on the return. again 2m up 2 elbows. 30 m run 2m down 5 elbows and 2 engineered bends. to the pump then to the ASHP about 2 m of pipe. So in all about 70 m 22mm copper. 30m of 32mm in the storage coil. 10 elbows plus 4 engineered bends. The heating and radiator loop has been disconnected and capped as part of my trouble shooting, however with it connected the flow rate did not change. So for the purpose of this question please forget the heating pipes and radiators. I am trying to get the flow on the main runs. Other pipe size on the system is about 2 metres of plastic pipe with speed fit coupling on the flow and return at a section of the run where it had to go out of the eves of the house near the ASHP as the roof design is a complex hip and valley so no gable end to come through. Removing roof tiles would be the only way to resolve this to get copper in place. so knowing that the section of plastic pipe has a slightly smaller bore than the 22mm copper is this working in copper at 20.6 bore. I am reading that the plastic pipe could be as narrow as 20mm due to the speed fit inserts. is the pipe work now all effectively reduced to that smaller bore thus loosing 0.6 mm across the entire system and creating drag to increase the head ? Is my 22mm to small? Would a second pump fix the flow, and where does it go on the system? should I increase to 28mm? Would increase greatly to 28mm on the long runs only work? would a low loss header help and what size? i have read and googled hundreds of pages on this topic and have come to some of my own conclusions already hence the numerous questions. Air in the system has also been an issue probably due to the long pipe runs. I have an air release bake on the flow as me return above the tank at the highest point. It take a long time for the air to work out of the system and the pump flow is very variable eg. From low flow to 1.6 until the due is out. Then the pump hits 2 and run silently. many advice on the air problem is also appreciated. Thank you in advance for any advice you have.
  9. Can anyone of our electricians @ProDave please explain how this wiring diagram will work on my Panasonic 9kw Aquarea heat pump?Secon Panasonic H Series rev1.3.pdf I understand that the heat pump will require its own supply from the CU but I am a little unsure as to what cables to put in ready for my sparky mate to connect everything up. I think I need to run some 1.5mm flex to run the heat pump ,diverter valve and controls etc but not sure if the power supply for this is fed from the heat pump supply via some fused spurs or if the heating controls are fed from a different source to the main heat pump supply? I understand it would be ideal to have one isolator for the whole heat pump and assoc controls but just a little confused? The heat pump itself has a back up heater for DHW so this is also confusing me as it shows connections for the immersion heater in the drawings but I assume this is the one on my HW cylinder so not sure if the feed for the immersion heater should come via the main heat pump supply? I am just trying to get all my cables in place ( so I can plaster some ceilings ) plus some spare ready for when my sparky is available to connect it all up next month so we can get moved in before xmas and I still have plenty to do! Hope you can help me understand this? TIA
  10. Hello all, I am currently deciding on a ASHP for a 260sqm new-built home. Initially the plan was to go with an 11kW Thermia Atec as proposed by the supplier. Now I have seen Thermia has an iTEC version which is a modulating ASHP. By no means an expert, but what I have read so far is that the modulating heat pumps are superior compared to the non-modulating ones. Wondering if someone has experience, especially in those 2 Thermia ASHPs? Would you go for the iTec or the Atec? Next thing would be the size.... presumably 11kW are a bit oversized? It`s a newbuild with tripple glazing, 3 bathrooms and cavity walls (U=0.13). MHRV is installed as well - therefore I am inclined to go with a 9kW version. What do you think? Cheers, Tom
  11. Hi. If an ASHP has a rated input current of say 10amps (in this question I am ignoring the Maximum input current required presumably for start up) Does that mean that during the active time it always uses 10amps? By active time I mean when it is trying to produce a temperature change not just when the pumps are just running and the technical stuff is monitoring. Guidance appreciated
  12. Hi, Just talking to a supplier about which ASHP to go for in our project. It was planned all along to be the LG Therma V model with the split system because the outdoor unit has to be about 30m away from the property. It will be for UFH approx 240sqm and hot water. Does anyone have any advice on which of these brands above are good or not? The supplier is now saying he highly recommends Panasonic or Nibe and he says Nibe is probably the best one.
  13. Hi When does the installation of an ASHP installed on an existing building ( no building work required) under the MCS scheme ( under permitted development ) require Building Regulations notification? Are they just talking about the electrical work ?
  14. Hello, I've had my Samsung Gen6 ASHP running well since November last year. Very happy with it. However looking at the controller, there 'energy generation' figure is waaay higher than the energy consumed. It would work out as COP of 6-12! I've checked the consumption figure vs the separate meter on the fusebox and that it broadly in agreement. Does anyone know what sensors or calculations are used to calculate the energy generation so I can troubleshoot a bit further?
  15. Here goes - It seems I under estimated the area needed for my ASHP condensate pipe to drain away into, as the condensate has been backing up recently. [Not draining away via the soakaway created as expected.] Upon inspection, I thought I could just dig a larger area but unfortunately, the area I am working with is clay based. In fact I managed to dig down a good 900mm but all I have done, is to create a clay walled well! Yes, it will no doubt take time to fill up but it is not a "long term" solution. So, one possible solution is to connect the ASHP condensate pipe to a pipe which in turn will "tap" into a nearby down-pipe / gutter system - see image. My question is this - How best to drill / create a hole in the "gutter" / "drain" to accommodate the new drainage pipe without breaking it and causing me all sorts of additional problems' As ever, your thoughts are welcome.
  16. Evening all. We have moved to the next stage of the now extended OVO sustainable heat trial (I.e. government funded heat pump trial), and have the preliminary system design for our year 2000 detached four bedroom in Kent 130sqm, triple glazing installed two weeks ago. The report shows calculated heat loss is c4.3kw. Don’t know how this compares to others but we have 300mm loft insulation and the triple glazing has significantly reduced air leakage and feels so much warmer than the battered twenty year old double which was replaced. The new doors In particular are much better. New ASHP system is a 7kw Daikin monoblock with a 250 litre Daikin cylinder. Four radiators are proposed to be replaced two of which are in the main bathroom and en suite - the former I am going to resist due to tiling upset. I raised concern with the heat pump firm, who appear to be very experienced with ASHP, over our downstairs rads being served by 10mm plastic microbore, but after the heat loss surveyor called into the office when on site they was happy that our reasonably modern home should cope. I however note that we have not had a buffer tank specified which is my main concern given reading on this forum. I am minded to go ahead without pushing the buffer tank issue, and if short cycling is a problem for the period of the one year trial potentially adding a buffer tank later. Is this a possibility or a complete headache if adding later? I assume it is a case of T ‘ing into the radiators circuit so can be “reasonably” simply added later. Can a buffer go in the loft above the cyclinder location? Assuming I build it into an insulated cupboard? As you can imagine the offer of a free heat pump system is very tempting even if it does mean there is the potential need for future upgrades to get the best out of it, hopefully not at excessive cost... thoughts appreciated
  17. I'm currently looking at a house purchase and a bit puzzled by the heating system. It's a 15 year old Nibe Fighter 360P ( which the original builder admits is a little undersized, the property is well insulated but 200m2 rather than the 160m2 suggested limit, they suggest it outputs around 5kW. We are looking to extend and would end up with 250m2, I also understand that the 360P is end of life and spares getting harder to come by so a replacement makes sense on all fronts. The house has the vents to capture warm air from the lounge and bathrooms and an exhaust chimney, with vents in the rooms for fresh air to come in (see diagram), UFH throughout and TRV to bedrooms. The house is very well insulated and fairly airtight. The options I see are 1. Replace the 360P with the updated model - the Nibe F370 this will be supported for longer, is a more efficient model and MCS registered so would qualify for RHI. However it still have the existing limitation in terms of output. With the Nibe systems in Winter mode then it will try to augment the heating using an electric coil and this proves expensive. The current owners supplement the heating using a wood stove, the heat from which is then captured and recirculated which is an options and I could go for a pellet stove which could be automated to some extent. 2. Replace the 360P with an ASHP, this will be more efficient and capable of heating the house without supplementary log stoves etc. This would leave the existing vent system so I had though that I could add an exhaust heat pump like the SunSystem TDA S 200 Sunsystem Exhaust Air Source Heat Pumps - Green Phoenix Ltd which would improve ventilation in the house and recover heat to compensate for the vents in the rooms, this would then provide DHW and as this unit has a coil it can be heated by the ASHP as well. I'm not quite sure how I would control these two together and whether this is overkill, all the houses I've had before have been sufficiently leaky to not require a ventilation system. Any input and thoughts welcome. Attached is a diagram of the 360P and vents, and the TDA S 200 manual. Thermopump_Exhaust_Heat_Pump-TDA_v0.2_EN.pdf
  18. Apologies if this has been asked before and if it's in the wrong category, but our M+E consultant is recommending a Vaillant ASHP which I'm fine with but when I look at the Vaillant UVCs, I'm concerned that they won't get the best out of the solar PV diversion. Most solar PV diverters have two outputs, so that once the first output has stopped accepting energy the second output is activated. So if you are doing what most people do, diverting to an immersion in the UVC for hot water, you'd ideally want to have 2 immersion heaters in the UVC, so 1st heat the top of the tank, then when that's hot start to heat the bottom of the tank. The Vaillant UVC has one immersion in the middle of the tank - so only the top half would benefit from the solar diversion. An alternative would be say the Gledhill StainlessLite Heat Pump cylinder but that only has a single immersion heater point which is at the bottom - theoretically better because on a good day you could heat all the tank but not on a marginal day as you'd only warm the whole tank up a bit. Anyone know of a cylinder suitable for ASHPs with 2 immersions - middle and bottom? Thanks in advance for any help. Simon
  19. Can anyone give me recommendations or suggest sites where I can find out information on what type of heating system I need as I'm CONFUSED. I'm a first time self builder and navigating my way through all the information and decisions. We are building a 300sqm house (approx 177sqm downstairs and 130sqm upstairs) It's an upside down house with living upstairs and 4 bedrooms downstairs. We are planning to have underfloor heating in most spaces (radiators in bedrooms), 2 log burners and MVHR. It's a rural location, no mains gas. The previous property used oil, we are knocking and re-buliding. We were planning to go LPG gas - but I'm told to meet SAP & EPC calculations we would need to put Solar panels in as well? We've looked at ASHP but get really mixed messages on this. Any advice greatly welcome... (Thank you)
  20. I am in the process of designing (with architects!) and commissioning a small low-energy house which will rely mainly on solar pv for energy. There is no gas at the property. I have over 15 years experience of solar thermal and solar pv. My current house uses solar pv exclusively for hot water for more than 7 months per year, uses gas for ch & backup hw for colder months. My current 3 immersion design cylinder has proved very effective. I have trawled through various heating and dhw designs including thermal stores and multi-tank solutions but cannot reconcile the different requirements (eg thermal stores need a good temperature gradient to provide dhw - heat pumps provide 55º as a working maximum). I have also noted comments on this forum. (“Hot water and heating are different – keep them separate!”) However I’m still looking for an efficient & effective solution. I am considering using a large unvented cylinder (say 500 litres) which will also act as a buffer for a heat pump and a thermal store for underfloor heating. For at least 8 months of the year the total input would be from solar pv through immersion heaters. For the colder months there would be the possibility of input from a heat pump. Primary heating would be through 3 immersion heaters. I have included a diagram. I see the following as advantages : 1. A single tank with straight-forward plumbing. No complex valves or diversions. 2. Separation of circuits for input/output. Antifreeze needed only in the heat pump circuit. - Better heat transfer to UFH with water than with antifreeze mixture. (and much less of it) 3. Ability to maximise use of solar pv (8kW) throughout the year. 4. Possibility of running as a fully electric system without heat pump - under consideration for at least one year to assess relative costs. Also provides alternative heating if heat pump fails. 5. Typically : we boost heat in the mornings (before 9.00) and in the late afternoon/early evening. Background temperature maintained at other times (although with a good store in the slab this will become less pronounced). Best efficiency from an ASHP will be when the outside temperature is highest and the best use of solar pv will be between 9.00 and 17.00. So having a facility to store heat at these times will maximise both efficiencies. I recognise one potential problem: In our current location, with excessive water hardness, cylinders frequently deposit more than 0.5kg calcium salts per year. We have completely avoided this by quality water softening and would do so in the new location. Although the physical design is simple the efficiency will depend on the control circuits. I propose to design & program these myself rather than rely on the current commercial provisions which seem to be over-complicated but still limit options to those provided by manufacturers. All of the plumbing would be installed by G3 qualified tradespeople. So I would welcome constructive guidance … 1. Is there any commercial system which already follows these lines which I’ve missed? 2. Has anyone on this forum taken a similar line – with what results? 3. Are there any genuine down-sides which I’ve missed?
  21. Hi, I live in Harrogate, North Yorkshire. My interest in these forums is the wealth of knowledge that I can see here specifically regarding Air Source Heat Pumps. I have an interest in some DIY - just lightweight really, however, my real focus is in green energy. We had PV Panels installed around 6 years ago now - 6Kw SolarEdge system located on three aspects of the house - E, S & W, combined with the SolarEdge Optimisers this gives us what appears to be a optimal install given the actual location of the house. In addition, we replaced our ageing gas boiler with a LG Therma V 9Kw R32 Split unit at the beginning of last year. At the moment I am looking at the last years running costs and wondering if the unit has been setup correctly. I'm not entirely convinced that any setup was done by the installer at the time. I look forward to reading more of this forum and chatting with other members! Andrew
  22. My planning permission contains commitments for installation of solar PV, air-source heat pump and rainwater harvesting. I'm not wanting to go through another round of planning variations so I will install them. However, I suspect if I'd done a full cost benefit analysis then it would be difficult to justify the rainwater harvesting in particular. The solar PV hardware appears to be getting much cheaper (haven't looked at install yet) but the Smart Export Guarantee tariffs don't look particularly attractive (5.6p/kWh). ASHP makes sense I feel as there is no gas supply available to site although some of the installed prices appear astronomically high (e.g. £11-12k). Does anyone have any evidence that these eco features more than pay for themselves in purchase premium on a house sale making them "no brainer" territory?
  23. Hi community, Over the last 2 weeks I've been trying to take in lots of info regarding ashp since having one installed in a new build, thanks so much to all the people that contribute with their esteemed knowledge, much of it on here is well above my basic understanding and it seems there are a myriad of things to consider when trying to optimise the systems. Bit of background, 186m2 timber frame kit from a company called scotframe, as a non builder this seemed like a means of eradicating some of the problems with builders as it progressed. Product has been good aside the nordan windows and doors imo, the erectors not so good, wish I'd hired a chippy with lots of new build experience to keep and eye on them but I am where I am now.. if anyone has questions about scotframe always happy to share my thoughts and experiences. Installed I have an ecodan 8.5kw system with ufh downstairs dfor heating and DHW. no buffer tank just the ecodan cylinder with 6 room stats downstairs. Vent axia sentinel mvhr yet to be commissioned / balanced. 75mm screed on top of 140mm celotex. pipe spacings at 125mm (mostly anyway). Been running now for 2 weeks, the house is at a comfortable temp downstairs, 17 deg, and that what's the stats are set at, not lived in yet but in this cold weather seems heating will be needed upstairs with points for electric heaters of some sort ready for the future. After lots of reading on here I've decide to run the ufh at a low flow temp, presently 29 degrees and run it continuously aside from peak pricing times with octopus agile.. . The house seems to hold heat reasonably well but until I move in to a semi building site in around 6 weeks I wont know exactly how it performs. Whilst the heat pump installer / plumber was a lovely chap and had a love for making perfect copper piping I'm not entirely sure how technical he is when it comes to these systems. I have lots of questions but the thing that's initially baffling me is on the control panel for the heat pump when the ufh is running its shows the flow and return temps are very similar circa only 1 or 2 degree loss between the two. From reading on here that seems far too narrow so the lovely heat the pump is generating heat but returning the majority of it . If someone could help me understand the impact this will be having on the heat pump / efficiency and then how I would go about increasing this difference that would be appreciated. The installer left all flow rates at 2.5 which was nothing like the ufh design I've referred back to, so a few days back I reduced these to what the design recommended, but this hasnt affected these flow and return temps which I assumed it would have. As said for many on here with knowledge in this area it may well be like pulling teeth trying to get me to understand what's going on but I'm game for the challenge Thanks.
  24. There have been so many little problems Ive asked for a break with the builders so I can do more research. Do I recall people discussing that UFH and ASHP might not be a great idea for a rental property? I'm not planning to rent the stables right now but its not impossible in the future. Is that because of the PITA factor and the chance of poor installation/incorrect sizing etc etc
  25. Hi I really appreciate all the advice and information on this forum so have finally registered with a question of my own. I have bought a house with no heating. We are going to install an ASHP behind an outbuilding and have already put in a heat main (twin 50mm pipes) from the outbuilding to the house, a distance of about 20m. What size pipe should we step this down to for routing through the house to the DHW cylinder and UFH gubbins? Is 28mm big enough? Thanks