JohnMo

50mm sounds small. My pipe going into the stove is aluminium. You can wrap in rockwool if you want. Rockwool doesn't burn

Mine was running for a few minutes while doing central heating, then being locked out for 10 minutes, this repeated over the day.

Not really, just use a 3 port diverter valve. My house started with a thermostat in each room, even with a big buffer ended with short cycling of the boiler. Basically have run this winter with no actuators on the manifold on weather compensation. Big saving on gas consumption 25-30% even though this winter has been much colder for us than last year. House temp pretty constant. Will be installing ASHP in the next month or so and intend to run just the same. But with a 3 port diverter diverting hot water to the cylinder as required.

Or you just drive the pump from the thermostat switch. I would use the manufacturer controller every time. Set it to weather compensation, balance loop flows. No thermostat other than the valiant control. Operate as a single zone. If you have a towel rad stick an electric element in it, to make it dual fuel. Good for summer towel drying. Also gives you two zones to comply with building regs

Could use a phenolic insulation boards like Kingspan Kooltherm K103 Floorboard. About 10 to 15% better than normal PIR, but quite a bit more expensive. Or normal PIR boards. Put it down in two layers with staggered joints, all a tight fit. Fill all gaps with expanding foam and tape the top layer. Thin polythene sheet, staple the UFH pipe to insulation through poly sheet and then screed.

No you don't need to make it each room a zone as you seem to be stating. If the property is over 150m2 you need two zones. No more than that.

I've use pipe in pipe, but not on anything domestic. Marine diesels use pipe in pipe if the pipe, should it leak, would allow fuel or lubricant on the turbo charger or exhaust system. Don't really see any reason to waste your money in a domestic situation for water.

Couldn't agree more. Our bedroom UFH is poor performing compared to the rest of the house. Good job we have the bedrooms cooler anyway.

Think you should tell the brickies about the new invention called a trowel. By the looks of they just throw their cement from about 6 foot away and call it a job done. No insulation?

Sad but true

I am afraid that's what the general public think and need a is simple Tag to associate low running cost houses with. Passivhaus - what's that, very small group of people have heard of them and understand them, most no clue, if they have heard of them they're airtight and must be stuffy and mouldy. That was the feedback I had from people I spoke to when I was building our near Passivhaus. Building education is very low in this country, with the general public and building professionals. Picking up on another thread, Tado sell smart thermostats to rest of the world, they degrade them for this country to on/off thermostats

Sounds a lot of money not convinced, didn't see anything on efficiency. Small A2A for heat and cooling?

Give it a go

Likely the loops or the piping leading to and from the boiler are full of air. How did you connect the UFH to the rest of the system? Do you have auto vent valves. Commissioning is the task of getting the air out the system, and setting pump speed, flow rates for each loop and setting flow temp. I have 7 loops, 3 approx 100m, the rest less than that. Pump is a Grunfoss of some sort, it came with the mixer.

Mine is 70mm logs, but will be insulated also.

Just to throw it in there ours is 6m wide and 4m deep. In the roof, fully insulated. It houses gas boiler big buffer and MVHR unit, but mostly full of stuff used as as store. Also have a fully insulated water shed, with all the borehole electrics, filters etc, 2.4m X 1.2m, this will soon house the ASHP expansion vessel, manifold and some electrics.

Daft question has the system been commissioned and flow rates set. If not it could be as basic as the flow meters are closed to min setting. Otherwise - Air in system the main issue when you have low flow, your boiler pump and the UFH pump should have enough power to move the water about. My manifold has a pump on speed 1 and is pulling and returning water without issue from the first floor, without assistance from pump on the boiler as well. Assume you had a plumber? If so get him back and tell him to fix it.

EcoAIR LC ECOWATT - dMEV

I am going to use a demand based dMEV fan. PIR or humidity will run it and then a timer will shut it off, all other times it will be off.

You are thinking too much. The inverter produces a higher voltage and I think frequency than the grid coming in to the home, so PV generation is used before anything the grid is offering - basically the grid doesn't come in to the home, because its voltage is too low. If you don't consume the PV generated electric, the electricity takes the next path of least resistance to the grid. You either get some money for the export or you don't. Capping the electric export via software within the invertor, just plays with voltage so it can't escape to grid. If you are using more than you generate, the voltage form PV falls and main electric comes in to your home.

and nail guns

Each loop is a single length of pipe, buried in concrete, once installed and covered in concrete very little to go wrong. During the concrete pour the pipe will be pressurised with air or water, so not likely to get damaged. Manifold is just a series of flow meter and either a manual or actuated valve for each loop - all pretty simple stuff. Much more likely to put a screw through a pipe hidden in a wall than a pipe under 50 plus mm of concrete.

I got the same on a new build also

They should be taking outside air in via a dedicated inlet. Also the stove needs to take all air from this duct, some don't

Not sure where you are getting your electric or gas from, gas is 10p and electric 34p. With a Heat pump and a CoP of 3, that's around £5 a day not £24.