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Okay, I have solved this. It took a phone call to LG tech support as the manual is far from being clear. Interesting before he would answer any questions re cooling, he first asked am I claiming the RHI. When "room thermostat" is enabled by the DIP switch on these LG Therma V units, the electrical connections have 2 thermostat inputs, one for heating and one for cooling. So I have tried it this morning. I have just connected a manual switch to the cooling thermostat input and lo and behold the ASHP fires up in cooling mode. In order to get the water to flow around the UFH and open all the right valves, I have had to turn the "heating" on and turn up the room thermostats. This of course now means that both the heating and cooling thermostat inputs to the ASHP are active. I am happy to report that cooling seems to take priority in this situation and I now have water at 18 degrees flowing through my UFH pipes. I will leave it running for a while and keep a check for condensation etc and see how cool the actual floor temperature gets. Now I know cooling mode works and is after all easy to initiate, my longer term plan is to get 2 small fan coil units, one for each of the main bedrooms. It will be easy to tee into the flow and return in the plant room above the garage via another motorised valve and then run the pipes through the ceiling above the main bedroom. If anyone comes across 2 small cheap Fan Coil units please let me know.

Don't do it... I would leave that stopcock alone, and then clean off the pipe above it with some fine emery paper and add in a full bore lever ball valve. Use that as your isolator, and leave the existing well alone.

I'd agree with @joe90, strap a bit of timber across the top of the ladder. It won't have much of a load on it, as most of the load in a ladder goes downwards. I'd probably use a bit of alloy tube, just because I probably have a bit and it'd be lighter to lift up.

Length of 2x4 (longer than width of window) screwed to top of ladder to bridge the window resting on the brickwork either side ( note, I used to be a climber and don’t hold with all this health and safety stuff, bit like @JSHarris mounting his new external kit!!!).

Re: Multi-split - for the one I have at least it's radials from the outside unit. i.e. if you have a 3 way outdoor unit, feeding three indoor units, you need a pair of pipes for each, 6 pipes in total (+3 control/power wires, +3 condensate drains). Running internally would go some way to avoiding the 'office block / kebab shop' look on the outside. But I guess if you're building from scratch and could design a system whereby the A/W ASHP also did cooling via fan coil units, you could minimise extra services and pipework. The world is getting hotter... I think it's certainly prudent to factor in cooling from the start.

Before anyone gets excited about CDM you probably need to read this thread ...

I was researching this when we were building and was horrified at how expensive this type of light was, in the end I found these; https://www.ledkia.com/uk/buy-apliques-b/464-randy-led-step-light-with-a-white-finish.html Which now we have them installed I love, they give off enough light that we hardly ever need to have the main ones on.

We full filled with earth wool Very warm house

If you want to blow/inject it, you could go for technitherm by isothane which is an expanding polyurethane. Great u value and quick to install but is expensive compared to blown beads As you have to get it installed by a licenced installer. There are other less expensive polyurethane foams out there, but depend on whether they are above or below DPC

I think you're right, that it's related to the water heating. Might be worth asking Genvex if there's any way to enable cooling, though. It may be that this is an option, perhaps like the one on our ASHP, that can be enabled, perhaps with a change to the firmware. The firmware for the Optima is on the SD card that plugs in to the underside, so it might be worth asking Genvex if this can be changed.

As an update I managed to clear 90% of the moss using a combo of ladders and skirting board with a long length a bamboo screwed to it. A bit like dentistry from afar but after the momentus thunder storm overnight I ventured I to the roof space with a torch at 2am and everything was dry as a bone. Bucket still cobwebs, not a drop in it. So moral of the story is get rid of the moss if you can! Copper idea is one I may try tho to keep it at bay in future. Cheers for all the advice as ever!

so nexgen and no thermal mass is the way forward? ?

Why bother, to much time on your hands?

Turn it round so the dent faces the wall.

Check with major lenders if it is acceptable. Halifax used to borrow against local authority, steel frame/corrugated clad houses when other lenders would not. I’ve been thinking the same about non standard construction myself and am leaning towards building with cavity walls and cladding the outside.Something I really didn’t want to do originally. Solid wall and EWI just up the construction cost, as many brickies like building what they are used to. It’s hard enough selling a house at the moment without limiting buyers too.

Couple thoughts - in a well insulated home you can do all the heating overnight from Economy 7 tariff, and the house will retain the temperature through the day. Even folks with lots of PV have to largely rely on this in the depths of winter, as that's when you need most heating and is when the sun is shining less. for cooling, you can redirect ASHP to cool via UFH downstairs and into a water-air coil exchanger for upstairs. This is exactly what we're planning. In terms of cost of running cooling, ASHP vs A/C unit shouldn't really be any different like for like. if you setup the A/C just to give a very short-sharp blast where it's needed and don't care it will heat back up fairly quickly it might seem cheaper than doing the whole-house with ASHP, but with water-air heat exchanger I reckon you could design the ASHP to have exactly the same profile as A/C if you wanted. (And for kicks: here's me just three months ago swearing I really was not going to get an ASHP. That sort of thinking doesn't last long after joining this place)

Yep they do - quite detailed too

I once had a corrugated metal roof that might be considered. a design feature now.......single storey, pitched roof, no internal ceilings we just looked at underside of metal roof ......edgy design not, actually just no materials available to put in ceilings......hot as hades and loud as a battlefield in rains. Was in Africa of course.

Unico Units are really nice - manufactured in Italy, and are very neat at 16cm thick. https://www.olimpiasplendid.com/download_area?name=Air Conditioners Without Outdoor Unit&id=1105

Yes, the main thing would be to find where the studs in the frame are and then make sure that the holes are positioned in the clear space either side of one. This should be fairly easy, as the internal service void battens are lined up with the frame studs, so a stud finder (or strong magnet to find the plasterboard screws) should be able to locate exactly where the studs are. The only other thing needed would be a nearby power outlet to connect the unit to. One of these is slightly noisier than a split unit, I think, because it has the compressor inside the house, but it's probably a lot quieter than a portable air conditioner.

Yes. I never found out the cause but the plasterer re did that bit free of charge and it has not blown again.

Depends on the rainfall rate, i have done a fair bit of assessment of rain noise while is aus, as they use metal roofs a lot. The CSR red book has some advice and rainfall reduction values based on a number of metal roof build ups.

I would be more worried about the copper pipe which appears to be set in cement corrosion ? and where does that copper pipe connect to under ground?--one presumes its not to a lead main --so its probably to a plastic one with a compression fitting ? maybe time to make it all plastic underground to above ground . I would , while you are at it --and stop old age problems later with the supply

As you may see on another thread, I have just enabled cooling mode on my LG Therma V ASHP. I probably won't get it done this summer but the longer term plan is to get two fan coil units, one for each of the main bedrooms and connect that into the system to give us cooling in both bedrooms.

It may not be on the top of your list, but you may want to consider rain noise and if you are concerned about it, to control it. Though if its a holiday house it may add to the ambience

Sorry I don't know the cost of it. I've only used it once which was on a commercial project a while ago. It worked very well and was very quick to install. I also used this product on a large domestic extension quite a few years ago. https://onduline.co.uk/products/ondutile/ I couldn't meet the minimum roof pitch for an interlocking roof tile so installed the Onduline under the tiles. As far as the Building Inspector was concerned the Onduline was the roof that gave the weather protection and the concrete roof tiles were purely cosmetic.

There's quite a few proprietary systems on the market for roofing that would allow you to do exactly what you asked eg: https://www.kingspan.com/gb/en-gb/products/insulated-panel-systems/roof-panel-systems/slate-tile-support-roof-panels-ks1000-ts

Your son and I were in well tune this morning then! I was thinking about the Ed's comment (re. pity not to capture the ejected heat energy to warm DHW_ and realized in summer this is marginal gain as the building needs to be a "net exporter" of heat energy to outside regardless, to battle against overheating. So rather than focus on capturing the wasted heat export (which low grade energy anyway) and bring back into the hot water tank, wouldn't it be more efficient overall to focus on capturing the wasted cold-air export when running the ASHP to heat DHW. Cue son-of-Joe. My proposed solution [see quick sketch attached] that requires no new moving parts, is simply to relocate the ASHP from ground-level up onto the flat roof at the rear of the house. We have 2 rooflights planned there, if I make one of them open "backwards" with the aperture pointed towards the ASHP, then it's a simply a case of cranking that open when the ASHP is in heat mode and the indoors is overtemperature. A 1.5m x 1m long rooflight with 25 degree opening will give 1m x 0.7m opening, enough to capture a good portion of the draft, and being cold it'll naturally drop down into the opening anyway. Downsides are numerous: the noise and possible mess of having it on the flat roof there, right overhead the dining area, and outside a bedroom window. Probably also needs the flat roof re-specified to be safely walkable, for servicing. But on the flip side, it would make the pipe runs to the services room way shorter and simpler (no need to go under the slab). Realistically, unlikely I'll consider it further, but always fun to think about further optimizations!

Personally I think it's wise to invest in better insulation and airtightness, than to try to fiddle SAP by adding stuff like PV that will inevitably need replacement at some future date. I've never, ever, heard of anyone regretting spending money on better insulation. Worth remembering in this hot weather that insulation works both ways. It keeps heat out in hot weather every bit as well as it keeps heat in during the heating season.

@PeterStarck It is the follow up company as far as I understand. With the difference if yours costing approx. 36k, they would charge you more in the region of 90k. Had a quote and few emails forward and backward with them but dismissed it really quick.

Want a job? ?

The ph15 system looks as though it was developed from the construction used for our portal timber I-beam frame erected in 2010. Our house frame was the second of that design built in the country. The frame which consisted of the sole plate, frames, racking and external rafters along with erection was just over £36000. We used Isoquick insulated foundations and Icynene wall and roof insulation along with external Rockwool insulation.

She means MCS, the organisation that acredit microgeneration installers. You need an install done by an MCS contractor if you are going to claim the RHI payments for an ASHP and previously needed MCS to claim the FIT for solar PV. There has been much discussion here about this. You can DIY install or just use any plumber / electrician often for a lot less than an MCS contractor will charge, and you need to look carefully. With a well insulated house, the energy use, and hence the RHI payments might be so low that it is not worth bothering using an MCS contractor or claiming the RHI

No, you don’t need these to be installed by an MCS installer in order to get the completion certificate.

That looks like our house build system. Insulated timber frame, racking and air tightness panels on the inside, wood fibre and render cladding. Ours was designed by a local architectural engineer and built by a local firm of builders, and finished mostly by me.

After one night, the answer is a partial yes, turning the air con off during the night does sort of work, but the bedroom was up at about 22°C this morning. Not too bad, but a quick wander around with the IR thermometer shows that the walls are all sitting at around 22.5°C, even those on the North side, so my guess is that a few hours of running the air con yesterday evening didn't take much heat from the internal structure, and that just radiated heat back into the room through the night. We could leave the unit on all night, at it's lowest setting, but I'm going to try just keeping it on all day today, to remove as much heat as possible from the internal structure, furnishings etc, and see what that does. I suspect I can get it to work much like the under floor cooling, by sucking heat out during the day, when the PV is generating, with the house then remaining cool overnight.

Fencing not obligatory - but worth it ...!! Stops you falling in a ditch or a wagon reversing into your footings (ask me how I know....) Sign in book is especially useful if you have trades on a day rate to validate invoices.

I thought the principal contractor aspect had already been done to done within the forum and the consensus is that as a domestic client the duties do not apply.

Been in touch with them. It really depends on your definition of "budget". It s certainly not mine. about as much as porsche is "a budget sports car".

Thanks, @joth, the unit seems to work fine. My main regret is in not having realised that we might need more cooling earlier, and including ducts to run the pipes and cables during first fix. What I should have done, perhaps, is just make provision for running pipes from the UFH up to fan coil units, together with cabling, as we have lots of spare cooling capacity from the main ASHP, all we need is more cooling upstairs (downstairs seems fine with just the floor cooling). You could run insulated 1/4" and 3/8" copper pipes in, ready to be flared and connected, as that seems to be the standard size for small to medium power indoor units. I'm afraid I don't know how the multi-split systems are connected, but would assume that they have a radial piping system from the outdoor unit. The copper piping is reasonably flexible, if a bit awkward to handle, so pre-installing it may make sense, rather than just putting ducts in place.

Quick update. Truespeed returned my answerphone message first thing Monday morning, and sent a jnr tech guy for a visit Mon PM. He could see how the cable is impeding my build and said he would raise it to the next management level. Tues PM, site visit from Snr tech guy who confirmed that the cable will be permanently re-routed with the work scheduled for Thurs. Excellent result considering I was expecting to have to grovel or get legal or threaten to chop the bloody thing down!

Just to close this off, I finished commissioning the Toshiba unit this afternoon (good timing, probably the hottest day of the year). It was delayed by me not realising I needed an adapter to allow the pressure gauge I'd bought to fit the test port on the outdoor unit - took a week to arrive. It was also a bit of a palaver hoisting the 23kg outdoor unit up on to the wall bracket. Apart from that these things are pretty easy to connect up and get going. I bought a package which consisted of an indoor unit (with remote), an outdoor unit, 4m of insulated pipework, with pre-flared ends, and a wall mounting bracket for the outdoor unit. I had to buy a length of 3 core 1.5mm² flex, plus a length of outdoor-rated 4 core 1.5mm² flex. I also chose to buy a vacuum pump, pump oil and a set of test gauges. Total cost for everything came to: Toshiba MIRAI RAS-10BKVG-E 2.5Kw/9000Btu outdoor and indoor unit, inc. shipping and VAT £574.08 4m pipe set £62 Wall mounting bracket £21.15 Trunking for pipework and cables £32 Cables £15 10m of 16mm bore water drain pipe £16.99 Total for parts used in installation £721.22 In addition, I had to add another double gang outlet to the upstairs ring final, tucked away in the service room. I happened to have a spare metaclad one, and the cable was easy to get at, so it was only a ten minute job. The unit plugs in and works fine on a 10 A fuse in an ordinary plug (the indoor unit is designed to accept flex, rather than T&E). I also chose to buy a vacuum pump for £42.99, plus a set of test gauges for £25, some vacuum oil for £6.25 and an adapter to convert 1/4" to 5/16" for £5.18, so £79.42 on tools. I'd be happy to lend these out if anyone wants to have a go at installing one of these things - not easy to post, though, as the pump is now full of oil. Installation was not difficult, but hampered by doing the job on my own. Coming up with a way to hoist the outdoor unit up on to the wall bracket, mounted just under the eaves, took the best part of a day, and was a real faff. The rest was pretty easy, run a duct through the wall (a bit of 68mm drain pipe is ideal), screw the indoor unit to the wall and hook it into place. Carefully unroll the copper pipes and feed them through the wall and connect them to the short pipes that come out of the back of the indoor unit. Connect up the 16mm drain pipe and run that outside and down to just above ground level. Connect the 3 core cable and 4 core cable to the indoor unit, and run the 3 core to a 13 A plug somewhere easily accessible. Run the 4 core cable outside with the pipes. Connect up the pipes to the outdoor unit, with a bit of vacuum oil on the threads and flare fittings and tighten them up. Connect up the test gauge and vacuum pump to the test port on the outdoor unit and pump the system down to vacuum, checking for leaks by turning the pump off, closing the valve on the test gauge and waiting to see if the pressure rises. If all is leak tight pump the system for around 15 minutes, to get any water out of the pipework, then turn the pump off and leave the system under vacuum for a while as a further test for leaks (I left it for over an hour whilst I had lunch). If all is well, then wire the 4 core cable to the outdoor unit, remove the test gauge, cap the test port and remove the caps over the gas valves. Open these to let gas into the system with a 5mm Allen key, then replace the caps and do them up tightly. Turn on the power and it should work. It seems to be working very well, and is extremely quiet, even when running flat out. The bedroom temperature is now heading for 18°C, so we should be able to get a good nights sleep. I think my timing has to be just about spot on, getting this running on a day like today. Time for a nice cold glass of wine...

Out of interest, why would a heat loss spreadsheet care about the heat source? I can see that the heating source would be of use in a running cost comparison, as costs vary a great deal, per kWh of heat delivered, between different fuel types, but can't see how the heat source can have any bearing on heat loss/heating requirement (as heat loss = heating requirement for any given set of conditions). I recently did a running cost comparison, for a typical year for our underfloor heating with different fuels and came up with these figures, which may be of interest (costs include standing charge/LPG tank rental, etc) : LPG fired boiler running UFH = £336.49 Peak rate electric boiler running UFH = £329.05 Oil fired boiler running UFH = £218.91 Off peak (E7) electric boiler running UFH = £206.43 Mains gas boiler running UFH = £143.76 ASHP at peak peak rate running UFH = £102.87 ASHP at off-peak (E7) rate running UFH = £89.25 Arguably the standing charge for all the electric heating options should be reduced in proportion to the ratio between heating electricity use and non-heating electricity use, as that standing charge will apply irrespective of the heating system used. I didn't bother to make that adjustment, but it would tend to reduce the cost of the electric heating options by around £40 p.a. or so if I was to do this.

Not a moment too soon to have installed an aircon unit. 35°C here tomorrow!