ProDave

Is that flooring "structural"? I very much doubt it at that thickness, so it will expect a firm flat stable base to be laid on. The UFH system does not fit that description on it's own so well need something like ply to provide that base. Our own Oak flooring was bought specifically as a structural floor board and is a lot thicker about 22mm iirc and being suitable to lay directly on the UFH and be a structural board to span the 400mm centre joists was a requirement given to the supplier.

You want old school heaters, NOT this LOT20 rubbish. An old fashioned storage heater that is nothing but a heating element a thermostat and a pile of bricks would work but almost impossible to buy those new now. For simple panel heaters, a bit less hard to find non LOT20 heaters. The simple plug in ones (that can be wall mounted but not very pretty) are still widely available https://www.ebay.co.uk/itm/334170215917?epid=8033159787&hash=item4dce18d5ed:g:2V8AAOSwjVthWyiX These are available in any number of places e.g are on sale in our local hardware shop etc. I paid about £20 each for our ones.

Well at least you did it in manageable byte sized work packages. And glad to know I am not the slowest builder on the forum.

I have my (home made) PV diverted connected to a 700W convector heater as an additional load, mainly for when the surplus PV is more than the immersion heater can sink on it's own. It does not come on at this time of year, what little surplus there is easily gets absorbed by the immersion heater. But it is useful mainly in the spring when it is still cold enough to need heating but the solar PV is usually doing well.

I think that is a technical analysis of an issue I have observed before. A plain brick wall of a house will absorb moisture from rain. In a typical house there is enough heat leaking out through that wall to keep the surface temperature of the wall above 0. Insulating the inside too well results in the outer surface of the wall getting below 0, and any moisture in the wallfreezing, expanding and the bricks failing. This is very noticable with garden walls, that have no heat escaping through them, and the fail due to frost damage. A near neighbour has re rendered his garden wall several times and within 2 years the render has failed and fallen off due to this effect, that would not happen with a house wall.

Your heat pump is presently connected to the main 24/7 supply so will presently get billed at the peak rate mostly. If you moved the heat pump to the bottom consumer unit, one of the bank in the middle like the now vacant one that used to feed Bed+Bath that would put it on the permanent cheap rate feed. Any competent electrician could swap that over for you.

Right, this THTC tariff. It was something unique to SSE (I believe also in the southern half of SSE) and at the time was sold as "total control" It is basically a normal off peak tariff that I think broadly mimics Economy 10 in that you get 10 hours of off peak rate over 3 different periods. The off peak supply feeds things like storage heaters, but it sounds like you don't have those any more. That accounts for one of your electricity meters that is a normal dual rate meter. The thing that makes THTC unique, is the second meter gives you a 24/7 always on cheap rate supply that is supposed to only be used for "heating appliances" which includes a shower, electric panel heaters, and of course in your case the ASHP. So check that when the ASHP is on, it is the single "total control" meter that is counting up and you are being billed at the cheaper rate for that. Your fuse boxes will usually be complicated and at least 2 of them, one bank of circuit breakers should be labelled "total control" and it is one of those that your ASHP should be connected to. Now the bad news, the SSE THCT tariff is not a good rate. It is also very hard to switch suppliers as most other energy suppliers can't cope with the metering. I believe @newhome did manage after a long search to find another supplier to take on the THTC supply and she got a better rate by doing that. Perhaps she can come and join in and give advice on that? I am not familiar with the Ecodan heat pumps so I will let someone else answer specific questions about settings etc.

It is almost impossible to buy an old style storage heater now. All you can get now are LOT20 compliant types that have electronic controls. That of course means they need a permanent supply as well as the off peak supply. They also incorporate a convector heater. No doubt they achieve better room temperature control but that will to some extent be by using peak rate heating to supliment stored heat. I was asked to repair one once where the fancy controller had failed and the cost of a replacement for that made a gas boiler control PCB look like good value. There is nothing I have seen about these expensive posh versions of storage heaters that would make me want one.

Keep repeating the bleeding regularly, once you have let one lot of air out, the next lot will start building up in the "pot" ready for next time. There should be a pressure gauge on the manifolds or somewhere, after you have let a certain amount of air out, you will see that drop a bit. If so open the valves on the fill loop briefly to re pressurise.

It just wants something planting there. The burn has never (yet) got up to the height of that pipe.

Another vote for knock down and rebuild. you will get a MUCH better house and with the zero VAT no more expensive. there really is not much you would be saving of the old bungalow. Then add in the fact the layout will be based on what is there at the moment (or jet more knocking down) which will compromise the finished layout. Complete new build gives you freedom to design it without compromises.

Rainwater, nothing nasty. Agreed it could be more discrete.

This is nicer

If you are doing PHPP I assume you are aiming high. We only have UFH downstairs and no heating upstairs, and the bedrooms, the mezanine and even the enclosed loft space all remain warm, because they are within the sealed and insulated envelope. To my mind it is madness to try and exclude a loft space from the sealed and insulated envelope because it just gives you a whole host of extra details to insulate and make airtight, not least being the loft hatch.

Inside a well insulated air tight house, differential temperatures within the building really are a non issue. e.g. I can go up into the little bit of enclosed loft space we have, which is not heated in any way and has no deliberate air flow through it, but is within the air tight and insulated envelope, and is it just as warm as any other part of the house. Upstairs in the one bedroom that has the vaulted ceiling all the way up to the ridge, I can go up onto the mezanine level and it is no warmer than down at floor level. I think what is happening, is without the building losing heat, you don't get the convection circulation you get in an old leaky house.

Well done. I would want an inspection chamber or at least a rodding point very close to that junction.

Yes some nice slabs of Welsh Slate would do nicely. Flue is not difficult, use twin wall insulated flue for most of it, then you only need to keep that 50mm away from flamable materials. the roof penetration will be the hardest bit to detail, or take it out the wall at 45 degrees and up the outside. @Onoff some of us can look at a babbling burn from our living room or bedroom windows.

We chose vaulted ceilings because planning here demands a room in roof situation if you want 2 storeys. Vaulted ceilings with gable ends and roof hung from ridge beams gives maximum usable space in the loft rooms. And then insulating them as a warm roof is by far the easiest way to detail a well insulated and air tight roof structure, which puts all the space in the house inside the insulated air tight envelope. I would do it again and go so far as saying the warm roof all inside the insulated envelope was one of the best design decisions we made. There is NO WAY I would want to do another build that tried to keep the loft space as a cold (and necessarily ventilated) space and still hope to get good air tightness and insulation.

If the heat pump supplier does not state in big letters that it is inverter driven, then it won't be. I would not buy anything other than an inverter heat pump for a house.

It is used regularly here for external render. Use "Snowcrete" instead of ordinary grey cement and the colour of the sand makes a difference (though you are often just stuck with what comes out of the local quarry) So a small mix and try a bit to see what it is like.

You will need to keep on doing it as that little "pot" under the bleed valve will only hold a small amount of air at a time.

Timber and plasterboard. It will be quicker and cheaper, and probably faster. Easier to change your minds, and your electrician will thank you.

That black thing, top right of first picture, has what looks a bit like a car tyre valve cap sticking up. Loosen that and you should hear air hissing out. Keep doing that regularly on both / all manifolds and eventually you should get it all clear, but it could take a long time of keep on doing this.

People scorn putting an mvhr into an old house that is not particularly air tight, but I suspect in this case it will work well. My impression from owning a 1930's house is the actual walls are pretty air tight, it was usually the rubbish windows and doors that made them leak like a sieve. In the old days, constant air going up the chimney from the open fires would have kept them fresh. MVHR would give you a constant rate of air change, which need not be very high, while avoiding the problem of the incoming air being cold.

The thing in the picture is a flow meter, to check there is enough water flow rate to the ASHP. It's when a pocket of air goes through it that it jumps wildly and makes all the noise. As others have said the system needs bleeding. You might just manage it over time bleeding air out of all the bleed valves. Do you know what they look like and do you have a suitable tool (if needed)? If your plumber has failed to find any bleed valves and is mystified, you need a better plumber.