Search the Community

I have an ASHP for heating and hot water. Unless I use the “luxury” DHW setting, my shower mixer adds too much cold water as it requires the thermostatic valve temperature differential to be 12 deg C. Does any one know of a shower mixer that will work with a heat pump hot water cylinder feed, i.e with DHW between say 40 to 45 deg C, rather than at above 50 deg C?

New build originally designed around a gas boiler and UFH, flow temp are low as could be, due to 300mm pipe centres. So previous setup was, gas boiler, big buffer, mixer and pump on the manifold. The flow temp out the buffer was consistent, but filled based WC (Weather Compensation) curve. Flow temps varied between 26 and 34 degs (at -9 OAT). The heat pump is installed without a buffer, all UFH loops open, with no actuators, mixer or pump on the manifold, so as simple as it gets. Have a single thermostat, just to give a start permissive for the heating. Couple of observation 1. The min heating temperature of the heat pump is 25 degs, dT is 5.4 degs, so a return temp would be 21.5. 2. After one heat cycle at a low flow temp (26 degs), the floor doesn't cool down enough to allow to ASHP to start up again. So heat pump would not restart. That didn't work 3. At low loads heat pumps cycle, I typically have a 10 to 20 minutes run time and 45 minutes off. The recirculation pumps continues running at all times. If the heating load decreases (OAT, solar gain etc), the heat isn't transferred out the flow as quickly, so the off period of the ASHP increases. 4. To compensate for the on/off run nature of the ASHP, and to get the required heat into the floor, you need to flow at higher temperatures at low loads, than you would expect. 5. So to make up for the on/off nature I increased the flow temp to 29. The flow temp pattern through the floor is typically (8 deg day), heat pump ramps up to set temperature and when it cannot modulate to control dT the heat pump shuts down. The flow temp and return temperature stabilise down to about 24 and flow will slowly cool over over the next 40 minutes, down to about 23 and the heat pump starts. 6. Very small increments in flow temp have an impact on house temp, less than 0.5 degs change in target temp, can be felt in the house. 7. Been tracking the temp on a Shelly H&T today, temperature drift in the house is around 0.2 degs. Have tested the 3 basic modes of operation so far, operation controlled by thermostat, batch charging overnight on cheap rate, and continuous running 24/7 on straight weather compensation. So far leaving it to run all the time seems the cheapest to run and easiest to implement. Have a simple Shelly H&T set up in the hall, to record how temperature moves over time and OAT changes, this will allow fine tuning of the WC curve.

New mini store water tank from Newark Cylinders designed with Heat Geek. Specifically for ASHP, with 40° water temp requirement. Not an unvented Cylinder apparently. How it works video will be up tomorrow.

Many heat pump suffer short cycling or fairly short run times in shoulder months, mine included. So in an attempt to understand this more clearly and hopefully developing a coping strategy for all I am after some information. Water leaving temperature will have a target temp let's say 30 degrees, the heat pump has hysterisis for stopping and starting around this temp. So mine (Maxa) it is To start heating CH water the return water needed to be target delta T (between flow and return) + and adjustable 2 degs. So at 30 Deg the flow has to of reduced to between 22-23 Deg. To stop heating the overshoot is allowed to to 0.2 degs over so 30.2 degs. Grant/Chofu heat pumps are Start 8 degs below target (22 Deg) Stop 1 Deg above target (31 degs) The above are adjustable settings What is yours? Make Heating type - radiators, UFH or mixed. Another interesting feature is circulation pump option mode. Run always when there is a heating demand and sniffer mode, with only periodic running of circulation pump, one for a minute off for 10 mins. Do you know how yours operates?

Plenty of information on ASHP is available on this site and very little on hybrid heating systems, i.e. boiler and ASHP. A few manufacturer designed hybrid systems are also available. When we built our house it was with an Atag gas combi boiler. We then installed an ASHP mostly for cooling, but it also heated our house well last winter and provided hot water via an UVC. The system below could easily be replicated by anyone wanting to install a hybrid heating system meaning little or no changes to heating system such as radiators. So the Atag boiler only 2 years old has sat idle for the last year. For periods where the CoP of the heat pump, means gas is cheaper why not marry the boiler and heat pump together. Most of the off shelf solutions, rely on the gas boiler doing the hot water, not what I wanted. Most the time the ASHP is way cheaper than gas (especially with solar). So makes sense to do hot water via the ASHP most of the time. Most ASHP already have all the control logic for hybrid mode built-in - mine does. I have a few location issues which makes the implementation a little more complex than I could be. Boiler and UVC are about 20m plus away from the ASHP, with UFH in the middle. The solution I chose to use has the boiler on a separate circuit to the ASHP. Combi DHW tails are not connected to anything and the isolation valves closed. Phase one Get hybrid hot water heating. Had a 40 plate PHE sitting doing nothing, so inserted in the flow line from the ASHP close to the UVC, the other side to combi boiler heating circuit. Set max flow temp to 60 on the gas boiler. I can change the rate at which the boiler adds heat (gradient), set to a max of 2 degs every minute. Initial run was all manually done to check concept. With ASHP only the reheat time of the UVC is around 40 to 45 mins, with boiler engaged about 20 to 25 mins. During test, I monitoring the ASHP and gas boiler and both work well together, neither running away temperature wise. Now how to automate. All control logic is in the ASHP, to use a boiler as a secondary heat source, you can set different outside temperatures for the following control schemes - 1. ASHP only, 2. ASHP leading, boiler following, 3. boiler leading ASHP following 4. boiler only. ASHP controller supplies 230v as a control signal to the boiler. But boiler is 20m plus away from the ASHP. So used a Shelly relay at the ASHP end and a remotely controlled Shelly relay at the boiler end. Set up a scene in the shelly app, switched live to ASHP end Shelly energised the boiler end Shelly relay. All worked fine. Set the hybrid mode (ASHP leading) to start at 7 degs and a delayed start of 10 minutes for the boiler, after cylinder heating starts with the ASHP. PHE, boiler on left side ASHP on the right. Phase 2 UFH - coming next.

I have a boiler that needs repair or replacement in a rented house, and I'd welcome thoughts. The situation is: - I bought property to rent to this tenant in 2016. It is unusual in having 3 double bedrooms, which was why they wanted it. - Good tenant, and I expect the family to stay for another decade (kids are 5-7 old years in local schools, family are all here incl. parents and siblings). They love the house. - It is a 2016 renovated 1910 done by someone else I bought it from - solid walls etc. Not to my standards, but adequate. I keep having to have bits done, which is fine but a small pain. - T is in receipt of housing elements of UC, and child benefit (whatever it is called now) -> may be eligible for Eco4 scheme, which is boiler replacement, or a Heat Pump grant for an ASHP. - Boiler (8 years old) is repairable, but not the best brand. Engineer recommends replacement (they would, but I'm inclined to agree) with a Baxi. I am mainly Ideal or Worcester Bosch. Repair cost £500-1000 suggested. Replacement cost £2-3k depending on model. - EPC is 60D on the sheet, but imo is better than that (I've done a few things, and there are some 'average' assumptions in there.) Had I renovated it that would be at around 75C. - Implication of that is that fitting at Heat Pump could get me over the EPC Grade C requirement which will be coming back at some stage, after Rishi Sunk's "how can I save my arse" 2 year panic attack burning all their achievements - including the landlord EPC ratchet - down. - T says house is comfortable running at a lowish boiler temp (need to check that). - My long term intention is that I prefer no gas (safety and hassle reasons). Options AI see it I have 3 options. 1 - Replace boiler, ideally under boiler upgrade scheme. 2 - Go ASHP with a grant, perhaps via Octopus. Octopus use I think Daikon units. 3 - Go with A2AHPs with a couple of multisplits, and units in relevant rooms. 2 and 3 would require a hot water tank to have space found. Should be doable. I'd welcome all comments, especially around if the Octopus ASHP packages are good, whether ASHPs are easy to manage for tenants, and what lifetime I can expect from ASHP or A2AHPs. Thanks Ferdinand

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

Hi - got my ecodan R32 installed in October and it's been purring away ever since quite nicely. This morning, in Edinburgh anyway, it was near on 0 degrees and there was a noticeably louder noise coming from he unit, as if the fans were spinning much faster etc. I gather it's normal for an ASHP to work harder, and therefore be noisier, when it's cold? When the manufacturer publishes its decibel rating, is it best case or worst case - i.e. on a lovely summers day when doing a DHW top up or at -5 degrees in winter? Thank you in advance!

Hi All, i recent brought a Vaillant AroTherm plus ASHP and have started to install it with a set of Vaillant AroTherm plus flex hoses that I purchased from City Plumbing. https://www.cityplumbing.co.uk/p/vaillant-arotherm-flexi-hose-750mm-20165288/p/130849?text=Vaillant AroTherm fl Previously it has been possible to shorten these flex hoses as the work the same way as solar thermal hoses. see here: However it Would appeal that they have changed the why they manufacturer the pipe. As there is no longer a circlip or bolt that fits over the corrugated pipe. Does anyone know where I can get a nut and circlip that I can use to shorten these flex hoses? The reason I need to shorten them is so I don’t end up with an air lock in the flex hose. hope someone can assist? cheers

I have an ASHP all installed and working. Also have a solar thermal panel - not installed, with a full drain back system. My issue I can't install direct to cylinder without quite a bit of work, but have very easy access to a roof space and ASHP flow and return pipes. So was thinking of coupling direct into either the flow or return of the ASHP via close coupled tees. Then put some logic behind it. Think return pipe would be better? So I need to do Take solar thermal when cylinder heating and heating UFH, but not when cooling. Typical flow temp for UFH is around 30, so should get a decent yield from ST even in winter. I could even switch off in the summer. What do you think, is it feasible?

Hi all, I currently have two Willis heaters (Read more here) providing the 6kW for the slab (proving very expensive now), I am now looking to get an ASHP installed. Question is, should I go via the BUS grant or should I source a unit off ebay and either attempt a self install or get a local fitter to install? I'd like to think that the grant would now cover the simple install! Further questions: How long does it take once the installer has applied for the £7.5k voucher? I'd like to have an install completed ASAP before the temps drop and there's a significant demand for heating in the house. The setup would be fairly straight-forward, with the heat just being fed directly into the slab, so no need for cylinder etc. Previously (2019) I had a quote for a Mitsubushi 8.5kW which also included the installation only of 2 Sunamp units (previously purchased but now installed) which came to £8,000. Presume that would have been a 2 day install at max, so imagine that realistically, today's figure would be less! I expect of course to get a much inflated price back when I go back for an updated quote with the excuse being short-supply of units, price increase etc. Self-install? So the alternative is to self install (with electrician), but would like to keep the controller KISS and the unit install itself would need to be a relatively simple to install and connect. I've done all of the plumbing including the Willis heaters (except the Sunamps) so would like to think an ASHP install is within my grasp. Worst case, I'd have to rope in a local plumber who has some experience of installs - maximum of a day I would think? Any feedback gratefully received!

Fan coil being installed in garden room to replace UFH, which really didn't work well unless at flow temperatures. Which wasn't an option with the ASHP and the main house heating demand. So Christmas eBay search led to me buying a Myson iVector MkII fan coil 1.2m wide. This unit can do heating and cooling and has a variable fan cut in temperature, so should allow me run weather compensation. Unfortunately the unit needs to placed on the opposite side of the summer house to the existing water entry point. So instead of running pipes internal, have decided to run them externally. Some photos of progress Unit wall mounted Cover installed The unit I got is a 4 pipe fan coil. This unit has a dedicated cooling and seperate heating heat exchangers. The heat transfer area of the combined heating and cooling HE's is about 50% larger than a 2 pipe fan coil. Have piped the two HE's as a single unit. I am using a Salus self balancing actuator to balance the flow rate through the fan coil. Have started the external piping using 15mm Hep2O and 25mm wall thickness insulation. The insulation to aluminium tape covered to keep mice away and UV to stop sun damage. The pipes sit on metal brackets 40mm off the ground and are galvanised banded into place.

Hello all, I was just chatting to my neighbour and we got on to the subject of her ASHP. She's had it operational for about 2 or 3 years and qualified for RHI for which she is receiving her payout from Rishi & Co. We'd been talking about firewood and I asked if she needed any, she said that she wasn't allowed to have a wood-burning stove (or any alternative source of heating!) under the conditions of the RHI agreement. Does that sound right? She mentioned how much she was spending on electricity each month to run the ASHP and I almost passed out! I suggested that she should consider PV panels to help power the ASHP and again she said that under the RHI agreement she couldn't install a PV system. This seems utterly illogical to me, is my neighbour misinformed? Thank you, Paul.

Further developments in ASHPs Higher output temperatures and greater efficiency achieved using new refrigerants. https://www.bbc.co.uk/news/business-67511954

We have a Cool Energy InverTech Air Source Heat Pump | CE-iVT9 4.3kW-9.5kW. We have had a DC Bus Overvoltage fault come up. Running since June 2021, its our first hiccup. The result was that the pump was on but not the compressor or the fan. We managed to turn everything off and turn it all back on and it fired up as per normal. However, in case it happens again does anyone know what might have caused this to happen? Regards Marvin

Hi All, We are embarking on a self-build and the ASHP was installed yesterday and we are awaiting the commissioning engineer tomorrow to turn on and start heating. I was a little alarmed by the our ASHP supplier planning to just operate the ASHP at its standard operation rather then operating a thermal cycle. From what I have read on line this is important for the concrete screed performance and any floor finishes installed later. I spoke with our tile installer and tile adhesive supplier and they have recommended the following regime which is more or less a 14 day cycle that involves, 5 days of gradual heat increase (2-3C per day) , maintain at expected operating temp for a further 4 days, before a 5 day gradual decrease in temperature. My question is with regard to the expected operating temperature, which I presume is the outflow temperature of the ASHP (45 degree), that the underfloor heating pipework's will be supplying to the screed for these 4 days. My understanding is that the thermostats will be overridden temporarily for the commissioning and the slab will be consistently heated with this 45 degree water - am I correct? If this is so then theoretically will the house be extremely warm for a few days as the slab should come close to the 45 degree temperature?

Hello buildhub residents. My first post here. I'm self-building a passive house in East Anglia and I'm looking at heating, DWH and potentially cooling solutions. My question is this - a load of companies seem to manufacture units that are either multi-split of mini VRF and have A2A refrigerant inverters available with a hydrobox for DWH (that's my reading of the marketing docs, please correct me if I've misunderstood the technology) But NONE OF THEM are available in the UK it seems (I hope I'm wrong, but I've called them and nobody knows anything about these units here). Does anyone have a good sense of why they're ether not bothering with the UK market, or why they're unable to get them licensed here? Maybe something to do with the distortions created by the Boiler Upgrade Scheme? The list has most of the big guys one it: Mitsubishi PXZ series - see around page 25 of this pdf here: https://kokotasgroup.gr/entypa/pdf/FULL_PRODUCT_HEATING_WEB--281-29_6166.pdf Samsung EHS TDM Plus Climatehub - https://samsung-climatesolutions.com/en-gb/b2c/our-solutions/home/heat-pump-solutions/heating-cooling/tdm-plus.html Daikin Multi Plus - https://www.daikin.ie/en_gb/product-group/air-to-air-heat-pumps/multiplus.html Panasonic Aquarea Ecoflex - https://www.aircon.panasonic.eu/IE_en/happening/aquarea-ecoflex/ LG Multi-V compact with Hydro kit - probably too big for my house, but anyway https://images.b2bmkt.lge.com/Web/LGElectronics/%7Bc5c4ca24-a96c-4aed-9cc9-97e1f6dbabf2%7D_2023_4Q_White_paper_Hydro_Kit_Low.pdf? ArgoClima iseries split - https://www.keaneenvironmental.ie/argoclima/iseries-split-pump/ Midea CirQHP- https://www.prnewswire.com/news-releases/midea-comes-to-ish-frankfurt-2023-with-its-latest-water-and-space-heating-solutions-301774592.html And yet - nothing available in the UK....

Hi all 👋🏼, I wanted to introduce myself and our project as I anticipate I'll be in hot pursuit of the forums thoughts, opinions and experiences in the forthcoming months. We purchased a 3-bedroom 1970's bungalow in August 2022 but had some planing complications due to a parish council policy that attempted to dictate that "a bungalow must stay a bungalow". 15 months later our planning application was finally granted, albeit with some compromises. Here's a few points on what we're attempting... Replace existing roof (& ceilings) entirely, building up the walls ~80cm, adding a new roof with 1.2m increased ridge height and steeper pitch Upstairs will accomodate two bedrooms, bathroom and "breakout area" overlooking hallway void Large single-storey flat roof side and back extension out to locate 65sqm kitchen/diner Complete re-configuration of downstairs layout Complete replacement of heating system (gas will be cut off entirely) New ASHP (current thinking Valliant Arotherm Plus, one-zone, no buffer) UFH all-round on ground floor (retrofit lo-profile UFH on top of the existing slab (Wunda?), insulated/screeded in new extension). Possibly fan convectors in bed-rooms upstairs Complete rewire I would assume MVHR (current thinking is a radial system installed through new posi-joists, manufacturer TBH but will get BCF to design) New solar panels, and battery (current thinking GivEnergy to unlock Octopus Intelligent Flux) New double-glazing all round (Residence R7 probably) also 2.7m high, ~8m wide sliding doors at rear (either Corteso Cor-vision or Minima) The biggest grey-area for us at the moment is how much to focus on/invest in improving the insulation and air-tightness of the existing exterior walls. I'll raise a separate thread for this in due course. Fortunately we were able to leverage a second mortgage and keep our existing home so we don't intend to live in the place whilst the majority of the work is taking place. The properties are only 0.5 mile apart so I am hoping I'll be able to keep a close eye on the build whilst I work from home. We are also intending to do a little of the work our-selves as possible (i.e. fitting MVHR, UFH, painting & decorating, airtightness membrane?, etc). Thanks for having me and in advance for any advice, Ollie Fleet, Hampshire Plans 24 OD - Amendments Combined.pdf Concept Images Existing Images

Hi all - The combined wisdom on here is unrivalled and I have picked up countless tips - ever so useful. So I thought I would pick your brains! We are still getting plans ready for the planning application. The house is going to be built into the side of a hill (with a gap of around 1.2m between the house and retaining wall.) It works out best for the views (and light) to have an upside down house with bedrooms on the ground floor and living areas on the first floor - where the front door will open out to the roadside. The light on the North/West sides is quite limited and it makes sense to put the plant and utility spaces here. Attached is an my initial thought on the layout of the plant/utility space and where to place any ducts - the plan is go for a fabric first approach which includes ensuring all the external connections go through the slab rather through the walls to reduce the cold bridging. My rational for the layout is: ASHP on the north façade - placed the un-vented hot water cylinder much further into the centre of the house so the bath/shower/washing machine are all close to minimise the hot water pipe lengths. By moving this to the Utility space I though it would then be a sensible option to have all the water centric kit (washing machine/dryer/UHC/UFH) separate from the electrical kit. Placed the inverter externally to avoid over heating (as suggested by Jeremy H) - it is not in sun light and there is a cover over as well. Is the layout sensible - any suggestions - all thoughts gratefully received. Thank you.

HI all. Would anyone with some knowledge like to give me an opinion on the AHP60 ASHP. Spec attached. its in conjunction with my other post, so run this to heat a 300L UVC for 2 camping pods. the money is good, brand new 3 year warranty. It is cheaper than the Dream units on ebay. and at this cost is sort of a no brainer unless someone see's a big issue. I've taken into account that parts if not local will take an age from China, but the immersions (on the tank) will be my back up. Might be convinced to buy 2 and use for the house as well... AHP60Spec.pdf

Following the Govs decision to give more time to introduce net zero. I kind of had it in my head we were to be stuck with ASHP with underfloor heating, although the installation would be hideously expensive and the usage not very much more cost effective than other heating types. It seems now we may not be stuck with one option given the extension and a longer time scale to make the changes. We are quickly sliding into our pension years and im now confused as to which system (no gas available) we should employ. Is there anywhere truthful where you can compare how economic all systems are. Ive googled and thats hopeless, one says ASHP another said Electric and ive even read that oil is!!! If I ask a plumber, of course they say the systems they supply are the best. Has anyone found any honesty?

Hi all, We are planning a new-build that will approach passivhaus standards, and I feel that going for the typical ASHP+cylinder+UFH is engineering and financial overkill, especially since we like to have the house around 18-19C and cooler at night. Instead I would like to have minimal electric radiators (or even just electric blankets) and something like the Mixergy iHP* to provide hot water at COP > 1. I would like to set it up so that it has two inlet/outlet paths according to external weather: If solar gain > heat loss: extract from top of vaulted glazed area and return to bottom to provide cooling If solar gain < heat loss: extract and return from/to external environment The second case is to avoid having to run the radiators to provide hot water on days with no sun, which tend to be wet and not sub-zero where we are building. Does this sound feasible? We will be getting an MVHR, but I was hoping that by having only internal/internal or external/external config we would avoid interfering with it's operation. Are there any products out there that would allow a compact solution for changing the flow path? It doesn't have to be automatic or anything, but I want to avoid a mess of flexible tubing. Cheers, Diarmid * other products are available, I just like the look of the warranty and modularity of this one.

It's been a while since I was here. "Life issues"...! Been using the willis heater set up for a couple of years now, and it's proven somewhat more expensive than anticipated, partly down to the electricity price rise fiasco. So I'm now looking to replace the 2x 3kW willis heaters that I had set up feeding the manifold for 150sqm of UFH. More here on my setup: 1) Presume the feeds from ASHP will be plumbed in directly to the manifold feed and return pipes, i.e. no buffer tank? I may leave the willis heaters in-situ as a backup. Probably looking at running the temps between 30-40c for 2-3hrs per day (bit more when it's really cold). This is current setup: 2) Siting the ASHP - the closer the better, but as I'm probably looking at around a 11kW unit, these can be the 'double stacked' types like this, and rather obtrusive to have this next to my front door (closest to plant room). I could site it a bit further out (approx 9m away from entering house) out of view and lay the pipework in the french drain surrounds the whole house - If I had additional insulation to the already insulated pipework would that be an option to consider for an quicker and easier install or would the heat loss still be an issue? 3) Can't afford to buy a new ASHP, so looking to get a used/reconditioned one. What are the best places to look at apart from ebay? There are some installers who are selling older but new models that come with warranty still, but any other sources I could consider? 4) What should I look out for in a used system? Obviously need to ascertain whether it still works, why it's being sold etc. Ensure that there are no refrigerant leaks, pump works, control board works... 5) How much should I look at for an install? I'm happy to dig any trenches, get cabling in by my electrician and do any preparation work to minimise cost. Thanks in advance for your feedback/suggestions!

Seen a couple of plate loading UVC's on offer for heat pumps, as opposed to a coil. So PHE and small pump taking cold water from bottom and deposits at top of cylinder after heating. One from Warmflow and the other from Mixergy. Advantages disadvantages?

Spotted a Daikin heat pump cylinder - 200L for a very good price. Model EKSWHU200B3V3 Does anyone know the coil size? Or any issues driving from a 6kW (max temp 60 deg from heat pump).