ProDave

What do you call "very cold"? My 5kW LG ASHP has continied to heat my house and DHW when it was -14 last night and now at a daytime high of -4. No doubt the COP is not as good and it has needed to defrost a couple of times, but it has not stopped working.

I bought a cheap "dirty water pump" from Screwfix for pumping the water out of my foundation trenches. By the time it had finished doing that it was not pumping very well at all, and a quick look revealed the plastic impeller had just about disintegrated, unable to cope with pumping a few stones. A quick phone call to SF they refunded and did not want the old one back as it was "dirty water" So if you want it for short term use and don't care how long it lasts do the same. If you want it to last, make sure you get one with a metal impeller. I refurbished mine with parts of another pump with a failed motor that I was able to recover the impeller from,

As many of you will be aware I am the owner of an LG heat pump, and older model 5kW version. I had some teething problems that have been well documented on here and largely solved by myself. I found their technical support to be wanting. I am loathed to criticise them however as knowing mine is an old unit I would hope the issues I had have been corrected on more recent versions and seeing as you don't hear lots of complaints about the issues I had that is probably the case. We were down to -14 last night, and my LG ASHP has been working without issue keeping the house warm and heating the DHW. We have reached a daytime high of -4 just now. I would be surprised if many of you have a lower outside temperature than here (unless you live near Braemar which reached -22.9 last night, a record low for the UK this century) If you want to experience worse, feel for a friend who installed an good energy ASHP last year, and it stopped working last night with an error message that meant "ambient temperature too low" I have not heard yet how he has got on speaking to the manufacturer about that issue.

Is an area of the under floor still saturated and that is just conducting the heat away to the sub floor?

What is the specific issue? If you are installing mvhr you will need a gap to allow airflow between rooms.

Just resurecting this thread. Had a call from the guy this evening. His ASHP is tripping with an error code when when her looks it up in the manual means "Ambient temperature too low" He is not far from me and suffering very cold weather, only he says they have freezing fog where he is. He will be phoning the manufacturer tomorrow. I will be interested to find out what the issue is.

Nails used to be normal to nail plasterboard, screws are a modern innovation.

My view is it only makes sense if you can buy the kit cheaply and DIY install it. It cost me £1500 to buy and install a 4kW system, which I recon is saving me £250 per year in electricity costs so will have a 6 year payback time. Self usage is the key, I am not convinced battery storage is there yet, when you fully cost batteries including end of life replacement, your "free" electricity is not that cheap after all. The only payment now is the smart (sic) export payment scheme that will pay about 5p for anything exported, but to claim that you will need and MCS certified install which will probably add more to the cost than you will ever recoup in payments. Had I been eligible (I am not) in the first 2 years I would have been paid the grand sum of £12 for my export.

Keep your chin up. I think just about everyone has a wobble of some sort part way through a self build when not everything goes to plan. Take a break, then go back to it with a fresh mind. Plenty have come up against serious problems and beaten them. You will too.

@Jeremy Harris Heat loss calculator is in this thread

I tried a long run at 110M and it worked, just, very slow connection. No way will it work 200M without something in the middle.

A room sealed wood burning stove should not hurt an air test much.

Yes I believe that is so. That does not bode well. What is one supposed to do when you chose and installed a system in good faith knowing it had a BBA certificate only to find it no longer has. It is worryingly beginning to sound like "not fit for purpose" which opens a whole new can of worms.

The issue is one of trust. Even when "fixed" will i trust it not to happen again in 5 or 10 years? Yes gutted does not come close. this has been brewing up for a while and I have pushed it back relying on the plasterer saying he will sort it for a while as I could not do with the distraction while still busy building, but now is the time to face it and shout until I get a resolution.

Thanks, excellent link. A snippet from that That fits what I am experienceing but there is no way I can see there is any case of "dimensional changes" and no issue with incompatibility or poor weather during application. Yes the EWI is low to the ground just on that garage wall. If that was the only area of concern then I could believe that was the caiuse, but that would not explain why it is occuring above doors and windows and in other places where the EWI finishes much higher above the ground.

Something like this to monitor one appliance at a time https://www.ebay.co.uk/itm/UK-Plug-in-Electricity-Power-Consumption-Meter-Energy-Monitor-Watt-Kwh-Analyzer/333855058767?hash=item4dbb4feb4f:g:36kAAOSwL0Nf~Xn7 One day I will buy one and get to the bottom of our "other stuff" energy usage. Plug each appliance into it for a day or a week and see how much everything is using.

No it is the house we want rather than a budget house. Decent levels of insulation, Rationel triple glazed windows, Oak flooring doors, door frames and skirtings, and not cheap doors. Granite worktops, both bathrooms as wet rooms. But everything was priced and sourced carefully, e.g. Internorm windows would have been twice the price or Ratioel.

No that is the mesh embeded in the base coat. I don't think failure of the base coat is the root cause, rather because that section of top coat did not get repaired, water has soaked into the base coat in that region and frost has cracked it. I have not started to peel back any of the delaminated sections to look, I am awaiting communication from the supplier before I do that.

Except the designer of the house specified the system and provided the BBA certificate, I bought the materials, and a plasterer applied it. It was not a contract job to a "render company" The plasterer has offered to rework for free (though that will be tested if the whole lot has to come off) and I am awaiting a response from the supplier.

Early on in our build in summer 2016, the outside of the house was rendered using the Baumit.com render system consisting of a lime based base coat mixed from powder called MC55W, a fibreglass mesh was rolled into this while wet. Then it was painted with DG27 primer and a top coat of Silikon Top applied. This was all applied to Pavatex wood fibre board cladding a timber framed house. There was a BBA certificate for this render system that I have attached. The result was crisp and sharp looking. But that did not last long. First winter, 2017 the first problem appeared, the top coat started blistering along the bottom of the east facing garage wall. It occurred while we were away over a cold spell, so thought perhaps it was a build up of snow along the bottom of the garage wall? (we came back to very thick solid ice all over the driveway). The plasterer came and re worked that using materials we still had left over. But since then the problem has spread. Next year it showed itself as just a couple of blisters on the East wall. But it has continued to get worse. After another year or 2 the blisters started to spread and the early ones started to crack. It is now in places on 3 walls, (none yet on the south facing wall) and along the top of one door and one window it has come away from the drip bead and is cracking all along the top. I have been trying via the plasterer for some time to get a resolution. He kept saying he was trying to contact the rep for the area to get him to come and look but with no luck, and of course all last year Covid has been the excuse. So while I don't have much else to do just now I have picked this up and tried contacting the supplier myself. First thing I find is the company that supplied it merged with another so are now trading under a different name, and the rep we were trying to contact no longer works for them. I have been given the details of a person that will deal with this so I have sent an email to start the discussion and hope we can find a resolution. In the mean time here are some photographs. This is the East wall, the garage wall. All allong the bottom it has delaminated from the drip bead, and all the way up there are blisters though they can be hard to see. Note the corner joint by the door is delaminating. Above the garage door on the east wall, delaminatinf all around the door and some hard to see blisters further up. Some of the east wall blisters close up, one has started to crack. Corner of garage east wall and north wall delaminating at the corner West facing wall, hard to see blisters in the wall and corner delaminating West wall above kitchen window delaminating and cracking And saving the worst until last, north wall corner of garage. This winter a chunk of the base coat fell off. I don't believe the root of the problem is related to the base coat, rather this is what happens with the top coat failed allowing water to soak into the base coat then the action of frost has cracked it. While I await a response from the supplier, I wonder if anyone has seen anything similar with a thin coat render system, if so what was the reason for the problem and what was the resolution? bba-certificate-for-nbt-timber-frame-rendered.pdf

What do you think will cause your wood flooring to warp / peel / rot or otherwise fail? Are you concerned about wet areas (kitchen) or the UFH? We have engineered Oak wood flooring throughout the living room, part of the entrance hall, and the kitchen / diner. When choosing it, we specifically said to the supplier recommend a product that will work with UFH and they came up with the large format planks we have, 180mm wide and up to 2.1M long. In the kitchen we just have a mat in front of the sink and hob area to protect the floor from spillages. So far (2 years in) it is all very stable with no issues.

Sory missed this first time around. Look in the instruction manual for the inverter. there should be a G98 conformance certificate from the manufacturer and you want the details from that, or just send a copy of that certificate. If you don't have one, contact the supplier and ask for the manufacturers G98 compliance certificate. Our DNO got a bit shirty because my inverter had "4000" in it's part number and they did not believe it was limited to 3.68kW until I forwarded the manufacturers declaration to say it was.

It sounds like you need to move house to the east coast somewhere?

Nothing but a tiny amount of condensation on the very edges of the glass on my Rationel windows. And I am sure it's a good deal colder here. I suggest a ventilation problem. Has you MVHR been ballanced? Are you using boost while showering?

How thick is this panel? UFH will of course elevate the floor temperature, so any heat loss through the floor will be greater than the same room heated with radiators where the floor would remain cool. so it is important to insulate a floor well for UFH. Yes it will "work" but how much of the heat that you put in will end up in the room, and how much will heat the under floor space and the outside? One member on here worked out that even with 300mm of floor insulation, he still lost 8% of the heat put in down into the ground. I personally think the company is being reckless to make the claims they are, I would take up all the floor boards, string a netting (netlon) across the bottom of the joists and lay rockwool type insulation between all the joists, put the boards back and put your UFH system on top.