JohnMo

If you just have towel rads on a separate control circuit, you will need a good sized buffer for your heat pump to stay happy. Why aren't you running weather compensation on a single zone? Keep it simple.

Have an outside light on a PIR and a manual override. Have the inside lights separate on manual switch or 2 or 3 way same as a hall light. Keep life simple, your Phillips hue lights should have been the wake up call, to keep it simple.

And doesn't chuck out plumes of steam etc, most of which isn't good for you.

Basically @joth says above. Nothing goes through the wiring centre now. It's just parking for a load of redundant wires. I have no manifold pump or mixer either now. Thermostat is a boiler permissive only, the only zone valve in the system is part of the heating system is in a garden room. But that isn't allowed to call for heat, it can just close heat off.

I'm with @gmarshall on this. The MCS standards may say approved bla bla, but the equivalent statement in English and Scottish permitted development rules are vague enough, to allow you to apply common sense. If you don't follow the guidelines on noise and piss of next door, you deserve everything you get. The normal person just does things - they don't read the rules or instructions, that's left to numpties like us, who enjoys reading rules and instruction books.

Or just don't have any actuators. I use my single wireless thermostat to give the heat source permission to start and stop. My existing wiring centre is still there, but I have nothing connected to it except the thermostat wires (those thermostats no longer used). The whole wiring centre is switched off. Not sure of your screed thickness, but the thicker the more time it takes to heat up from taking warm water. Can be several hours to see any meaningful temperature change in the room, if your water temp is too high room temp can overshoot, also depending on the thermostat you use, that can cause under and overshoot also. If you use a normal thermostat, that could have a hysterisis of upwards of a degree, if your lucky it maybe +/-0.5 deg. Any thermostat with thick screed needs a thermostat with a hysterisis of circa +/-0.1 degs.

As far as wiring and stats are concerned they are just an UFH actuator. But as a valve on the manifold closes or opens the salus valve open or closed to maintain a fixed dT across the open loops.

It actually say MCS or equivalent. https://www.planninggeek.co.uk/gpdo/renewable-energy/class-g/

Basically I have swopped over to a heat pump. But the weather compensation controller was/ still is in the lounge, I didn't do load compensation (no use with UFH), so that unit didn't operate as a thermostat. Have a single thermostat in hall. Only thing you have to watch is in the shoulder months you don't need much output, so you need to calculate how much water stays engaged with the boiler - you need approx 50L to stop 6kW from short cycling. So you need to know your water volume and min turn down of your boiler at low flow temps.

Finger in the air is not good enough for a heat pump. Are you saying you have no insulation under the slab? And your installing UFH? DT 5 will be generally required for a heat pump. Do your own heat loss calc, use the one in boffin corner. This is a whole house one, but certainly good for overall size required.

One of the reasons I used plasterboard pallets, high wall I made 2.4m high (2 x 1.2m), all others are cut down. Makes life easy for yourself.

First I would go for a more powerful one, a decent one will let you select the power output you need. You can then fine tune the output, if your 1kW ends up on the small size it just runs all the time. Also make sure it has a built in timer function and thermostat, so you only heat when you need to. Makes models? The other option choose any radiator you like. Add an element say 2kW and have a remote timer thermostat so it actually measures room temp. You just fill with water and some car antifreeze. More choice more adaptability.

If you are doing UFH (cooling) your flow temp doesn't want to much below 11-12 degs, but the fan coils would ideally be cooler. If you go that direction with ashp you would need a second flow temp, some do this out the box most don't. CoP A2A should be slightly better depending on which unit you choose, as there are big differences in performance. A2A can do both heat and cool equally as well. Both can give great CoP.

I did the 2.4m long walls on mine with plasterboard pallets. 2 pallets equals one wall.

Best to have them well out of the way, they can stick if the wind blows the vented air downwards.

Here you go, although you could have looked...

Why are you asking the same question again?

Depends on your architect and structural engineer. Could be a couple of weeks - months. How long is a piece string?

Sorry cannot suggest anything directly. There was recent thread on different makes have a look in the ventilation section.

Good luck getting that to work on building site and at scale. Think a battery would be easier and possibly cheaper.

What happens when you fill the cavity (block and brick) with poly beads, as those would not comply?

Basically you can't do anything before the warrant comes through (well you can, but not much). You need warrant drawings done by your architect and structural engineer. Once they are done you need the SAP report doing, structural design certificate, then you go through the 6 to 12 weeks going through the warrant process with the council. Once you have your structural and architectural drawings you can go for meaningful quotes and mortgage stuff.

No they would not fight each other. Air is slippery stuff, it just takes the path of least resistance. As long as extract and supply match each other reasonably well all will be good. dMVHR, can work out quite expensive and if not careful with selection can be more noisy than you may want

Hopefully a quick question. Background installing an unvented cylinder. Location is remote from the cold water manifold, preventing connection of the balanced port to the cold supply. House already has a PRV just after the stop cock set at 2.5 bar. Cylinder comes with a combined inlet set, set at 3 bar. Can I just blank the balanced line off? Do I need the second PRV to comply with regs?

It may be the difference between a breathable insulation and not breathable (PIR in this category)