JohnMo

Still all fine. The only issue is the sliding doors, leak like a seize.

If you read the instructions, they clearly state in the UK they are not allowed to go in a plug socket, they need to be wired back to the consumer unit.

Do you have a mixed system, radiators and UFH? He is describing a two zone system, you have a single zone. So there are radiators and UFH, each can run independently of the other. If you have just UFH do you need to mix down? Are you setup to up to run priority domestic hot water? Do you have the Vaillant wiring centre he mentions?

Active cooling allows comfortable rooms at much higher air temperature than you think you need. You simply do not need the room at 20 to be very comfortable. Our lounge is sitting at 23, currently and very comfortable (under floor cooling on) if a little too cool. Our summer house with fan coil is sitting at 22, again well comfortable. Was in it yesterday with full sun on it, it was sitting at 24, again a nice comfortable place to be.

If your chosen heat pump doesn't have an in-built mixer control you will have to add that, an ESBE valve and actuator aren't cheap either, a third party mixer controller isn't cheap either. Value adding possibly not. So a couple of layers of complexity. So now your flowing at 7 degs, to get max output from fan coils and mixing up to allow UFH, so need a temp above about 13 degs generally. So now just incase you have messed up you need to sense house dew point and make the ASHP do something different in case you start to get humidity issues. Another layer of complexity Then in winter you need more work arounds to get everything happy again for heating, where I assume you would just run straight WC? And another layer. Why would you be getting warm water from the fan coil? If your flowing 7 Deg water into fan coils, if they are running full chat you are likely to see a dT of 5. So return water is 12 degs, below dew point. If the fan coil fan is off because room is cooling enough the dT will be very low, so now you could be pumping water well below dew point. KISS.

No idea why you keep trying to make stuff complex. Just do it all above dew point. Then no mixer no second set point etc

This what I did. Ran mains water pipe mdpe to stop cock. Then converted to 22mm copper and to a cold water manifold. Then from manifold went below floor insulation running 15mm Hep2O in conduit to each room that needed cold water. All joints above ground, ample flow to each room. In theory replaceable, to comply with an obscure rule I found in building regs. You then have a central isolation point for each room that should be easily accessible. Allows each room to be commissioned at different times, and if you get a leak you can just isolate that room while it gets repaired.

Our original plan was loads of small down lights. We now have 6 in total in the kitchen diner, but they are no longer GU10 sized the are like 4x 200mm and 2x 150mm. Well bright, look more like light tubes in looks. Sorry small spots just look rubbish Use something similar to these https://www.screwfix.com/p/luceco-eco-circular-fixed-led-slim-downlight-white-18w-1530lm/663px

I would expect, because block work is made from concrete and when covered with plaster suck the heat from your hand. Plasterboard on the other hand with an air gap doesn't feel so cold. The difference will be also seen in room temperature stability the concrete blocks absorbing and releasing heat energy as room temps fluctuate to give stable room temps. The plasterboard version is somewhat isolated with an air gap will not function in the way. More akin to stud walls. I have always thought dot and dab is a bodge get out jail quick for builders, much like you describe, hide all the rubbish quickly and easily.

You would be surprised how well floor cooling actually works, plus how responsive it is. Plus you have it to try for free. Just run on fixed flow temp and let the heat pump look after itself. A slight leap of faith mentally, because have been brain washed to think we need thermostats etc. mine has been active (not always actively on) since April. Some days it doesn't even start, this afternoon it ran for 3 hours straight, but 20 mins per hour prior to that since 9am.

And about the most dangerous way to store energy. One reason you don't air test pressure vessels is the explosive power of rapid expanding gas or air should you get a failure.

Just tune the heating to be cooler. Or design radiator to match the lower room design temp

Set backs are generally a waste of time, you still need to replenish the heat back in to be building structure you lost during your setback. If running suitably low temperature for weather compensation, the flow temperature should be equal to supplying only the heat lost no more. If you are running the correct temps you never really recover. So instead, you end up running hotter temps than you really need and bouncing of the thermostats. Setbacks are a false energy saving sold by thermostat manufacturers to sell products. There is a handy calculator here https://protonsforbreakfast.wordpress.com/2022/12/19/setback-should-you-lower-heating-overnight/ So you can see for yourself.

Run in conduit then instead of you have a change of direction or just do a straight A to B to keep it simple

My view is very different from some on here. Ignore if you wish. Run on pure weather compensation, all zones open. Let the heat pumps native controller do the calls for heat as it sees required. Mitsubishi have a room biased temp modulation, but states this isn't to be used with UFH only suitable for radiators. Your system with lots of zones needs a buffer to work correctly, otherwise you will be getting flow related issues.

What are using if 22mm is bigger than 32mm waste pipe? All my cold pipes are are under the insulation in ducts, works well

Why do you need rads doing that output with a heat pump system? If you room has that heat loss you must be living in an open shed. Flow rate just sets dT, it is the mean radiator flow temp that sets the output. Why would you cycle the system on and off, or do you mean something else?

Pretty simple cheat sheet below. You really want to aim at zero hydraulic seperation. So 8mm will carry 0.75kW at a dT of 5 etc.

A quick Google search and the following pops up first hit Searched for "running mismatched pv panel parallel strings" Running mismatched PV panel parallel strings is generally a bad idea because it reduces overall system power output and can cause damage due to current imbalances. The string with the lowest voltage will limit the total voltage, while the string with the lowest current will essentially become a load on the other strings. This can lead to reverse currents, overheating, potential damage to the lower-performing panels, and reduced efficiency for the entire array. For optimal performance, it's best to keep strings with identical panel characteristics connected in parallel.

Not thermo wood, mine is Scottish larch which I don't want to grey. Use Cedar Cladding Oil / Decking Oil from Rye Oils. Goes on easy, lasts a couple of years between coats. No colour change in 4 years so far only done two coats to date

Not the same as a radiator calculation wise. You just need to read the datasheets. Generally they are designed to run sensibly flow temps and the datasheet will give a range of flow temps in cooling and heating and output at different fan speeds. In cooling my fan coil fan will only run when water sensor sees 13.5 degs and lower (ASHP compressor is actually on) AND room temp is above set point. Fan speed then changes automatically based on how much work the fan coil has to do.

Most decent fan coil will have adjustable setting for fan activation temp with different setting for cooling or heating. They are really rated in a given flow temperature. dT is depending on work done and fan speed. If you start flowing water below about 12 the air being drawn in by the fan is at dew point, so cannot absorb any more water, so water just stays water. Fan coils rated for cooling have a condensation tray to catch this water

A battery in the shed, connection to house, drive ASHP or A2A in shed plus tools. 15kWh battery plus interconnection cable £6k(ish), charge on octopus cosy - three cheap rates plus normal rate most other times. Allow battery to back feed house when not needed in shed. GivEnergy AIO has a 6kW inverter for charging and output loads. Anything above 6kW gets taken from grid.

The normal switch off sequence. Downstream of inverter or charge controller, you switch of the load path via a dedicated isolator switch. Then once isolated you switch off the PV panels via a second isolator switch. The isolation switches are suitably rated DC switches for the PV and again suitable rated for the inverter or charge controller (depending on if AC or DC). This way nothing goes bang including yourself. Reconnection is the opposite, you start at the PV and work towards the load. I really would just separate existing and new, way less complex, way more safe.

Would be careful doing that, you normally switch source off last, otherwise you be getting big sparks occurring on disconnecting or damaging the charge controller, or yourself.