JohnMo

Here is a simple graph. Oil has a lower condensing temp compared to gas

Heat up time is a combination of kW of heat input, and then how much concrete/screed you have to heat up, plus heat loss downwards. Not sure I would get to hung up on the DT until the floor is up to temp, even then not bother that much. The basic of floor heating system are The greater the mean flow temperature, the higher the heat output of the floor. The mean temp is set with a combination of flow temp and delta T. For a given flow temperature the lower the DT the higher the kW rate the floor will give out. As you have realised lowering the flow rate increases the DT. Your issue at the moment is the energy transfer from the water is too low to heat the room at an acceptable rate (its too slow). Increase flow rate, ignore the delta T. Get the room up to temp, your balancing act should be not overshooting room temp too much (flow temp not to high and/or DT to low) and not taking a couple of days to reheat (flow temp to low and/or DT to high). How much insulation do you have under the floor?

Our ridge beam is huge, something like 450x180mm if I remember correctly.

Our kitchen ceiling, 12 degrees has a 7m span with no steel. Our 45 degree roof has a span of 4.2m, without steel, except where the window opening is formed. Look at posi posi rafters

From what I heard a month or so ago, they have been taken over, not certain if they are back trading yet

MVHR flow rates are way to low to move heat from A-B, it will move some but the don't count on it. The air you supply to a room, will wash though that room, out an open door or under it and make its way to an extract point, so supply air moves the air anyway. You UFH manifold will be at a low temp so not much warm air to move about. Study I would make that extract only in your case. You can do the kitchen either way. But watch for grease mist entering the extract terminal, I have mine about 4m away from the hob, so grease is filter by the recirculation extractor first and have a foam pad in the extract terminal to capture anything missed by the recirc extractor.

Photos of your manifold, pump and mixer, would be helpful. When you say close the mixer - do you mean reduce temperature or increase temp? Are they the same mixer valves? Do you have a pump on each manifold?

Same with me for Durisol approx. 190m2 plus 3m tall, less than half that price delivered to NE Scotland.

Ours is in an insulated airtight roof section, walls and ceiling are nice a shiny airtightness vapor control layer - heavy items are mounted on off cuts of 18mm ply. Floor waterproof 22mm chip board. Under that is 200mm of Rockwool Flexi. Access through airtight insulated loft hatch with integrated stairs - all help keep noise away from the living space.

Lots of contradictions everywhere you look. In the end that's why I looked at Scottish Building Regs, the last thing I want is the inspector say no it has to move.

We used ubbink 90mm, if you look on their website and datasheets they have all the details on pressure drop and bend radius.

ASHP, shouldn't require anymore gubbins than a gas boiler. A monobloc heat pump will live outside - the gas boiler inside. You can use the same cylinder for either gas or heat pump, as long as you get one with a heating coil sized for a heat pump. Ideally you should operate the gas boiler exactly the same way as a heat pump this will ensure you are always condensing. Allow for a buffer cylinder, 50L to 100L should be fine as long as you don't oversize the heat pump. A buffer is worth specifying even with a gas boiler, to stop that cycling. So plant room will have a cylinder, buffer and possibly a manifold, if the MVHR is being located elsewhere. Your door sounds huge, mine all went in through a loft hatch.

There not cheap, just looked at the price of the 1.1kW £842 each

I was looking at, which is pretty much a standard air to water https://argoclima.com/en/prodotti/im/

Air to water heat pump ASHP. Not water to water, uses refrigerant to refrigerant. Instead of routing the hot refrigerant gas to an air cooler, when in cooling mode, they route it to a cylinder with a refrigerant coil. Disposing the heat to water. Once heating cycle complete it goes the normal route to the outside air. Argo clima is the make I have seen.

Some heat pumps (with the correct cylinder) will cool the house while heating DHW at the same time. DHW is heated free from the waste heat extracted from the house. If you have PV, cooling and DHW could be provided free in the summer.

You increase pump output/ speed. Or Increase flow temperature and decrease flow in the other rooms.

That's about the same flow as I have on my 100m loops. Are trying to achieve more heat in the room with those loops? Or something else?

Hello and welcome. Always a bit suspicious when they we don't need heating and the house is huge. So from the link the heat load is 11 W/m2, the floor area is 550m2, so on a cold design day that's 6kW. Where is that heat coming from, a couple of hours of sun in mid winter may heat a couple of rooms, but a few overcast days it's going to get cool, so I doubt the fire will be cosmetic for long. Small house 100m2, that heat demand is 1.1kW, small panel heater would do it on the coldest days. A2A heat pump, for heating and cooling? Cheapish to install, cheap to run. UFH, or fan coil units, small heat pump and UVC for hot water. Needn't be that expensive.

The other thing could a bird have nested in the flue, the nest dropped down and then caused a flue fire.

Couple of things to think about. The flue is a low pressure region, the natural way for thing to occur is not for the smoke to leak out, but room air to leak in to the flue. Has you MVHR been commissioned yet? Could you be extracting more air than you are supplying causing your room to be depressurised. On the same theme, combustion air coming from the room in a relatively air tight house, will also depressurise the room, causing smoke to leak in to the room. Two things to check, does your stoves primary and secondary air come from outside air supply (assuming you have one installed). Not all stoves do, some will take air from the room also. Is your outside air duct correctly installed and not blocked?

Our french doors also open outwards. Front door inwards.

The practicality really depends on your rooms heat loss do you know this?

Our boiler to ensuite is around 18m with a combi, a little waiting for the hot to arrive, but by the time you have you clothes off, towel where you want it etc, the hot water is there. Not much of an issue. Hot water cylinder would be quicker though. Would not bother with an electric shower. ASHP, can do cooling if you need it, gas boiler cannot. Heat pump economics £2+3k will get an ASHP, if you shop around. UFH is same for gas boiler or ASHP. The other parts with radiators, good chance they will need to increase in size, if micro-bore, this will need to be replaced, so this is a cost adder, a cylinder is required for DHW, with a heat pump coil. You can get a grant, but there is a good chance you can do it way cheaper without it, if your hands on. Energy wise, a well set up system will have CoP of 3 to 4, (1 unit of electric in 3 to 4 units of heat out). A gas boiler will have a CoP of 0.8, 1 unit of gas in 0.8 units out. You just need to look at the cost of gas/ electric. There are plenty of poorly implemented heat pumps. Insulation is your friend, so is airtightness and good ventilation with heat recovery.

Mine came with same oversized steels. I wanted more insulation in the ceiling than the depth of the posi joist/rafter, so counter battened out with 2x 50x50mm battens. That way I had about 70mm of insulation under the steel to reduce any cold bridge.