ProDave

It should have inhibitor in it to stop it going manky. And you don't shower with the water in the TS, that never gets changed. You shower with fresh water that passes through a coil in the TS, or a heat exchanger to get heated by the heat in the tank.

I read it as the existing kitchen, that becomes the utility has a low ceiling. The stairs go to a half landing above that then turn back to access the original part of the house. The bathroom is being built at half landing height above the low ceiling utility room, and thae are a few steps up from the half landing to the new bedroom in the extension. That must however make the new downstairs WC a low ceiling as well?

And once we had the ability to design and build our own Nuclear generation plants....... I am installing my PV as we speak (in between the snow showers) and hope batteries will be added later.

Sounds like the salesmen that keep pestering me offering to sell a "gadget" that will increase my PV output by 20%

It will harm self builders who want to sell an existing house to fund a new build but then find that house won't sell and they are stuck. Something I know a lot about. Just as it will harm someone that wants to move to a bigger house but can't sell the old one. My experience having been through 3 house market downturns, is the ambition to move on, move up etc is still there but you are completely thwarted in your ambitions if you cannot sell. And that all seemed in the past to be down to first time buyers simply not existing at that time. It won't help get all the houses built that our politicians tell us we need, as no builder will build houses that don't sell. If they are only predicting it will be as bad as 1988 it won't be that bad. I lived through that I was thwarted at my first attempt to move up from my 1 bedroom starter home because nobody even came to view it. A year later I tried again and sold it. That is nothing in comparison to the 10 years of house market stagnation we have had here since 2008

A Sunny boy will report on it's display the string voltage and string current. Next Sunny day you get, record those peak values that you see for each string.

Start by fitting an accumulator, that will maintain the 2 bar pressure until you have emptied the accumulator. A pump would need a break tank and gets messy. you can't just suck water out of the mains pipe with a pump.

Run the towel rail direct off the 1 pipe system, and just the UFH off the buffer with my idea of a 2 port valve and tank stat to limit the temperature in the buffer. Then for now you don't need a manifold and blending valve. You can add a proper manifold and blending valve when your next room is refurbished and ready to go, some time about 2025?

This is only temporary. @Onoff definition of temporary may be a bit longer than mine.

Surely only if it is designed as an unvented cylinder. A header tank, even without a ballcock would seem better. Just keep an eye on the level if you do that.

Agreed it needs a header tank.

I don't like the stairs pushed off to one side, they would be better in the central entrance hall. Definitely needs a door direct into the kitchen from the parking area.

Better would be a 2 port on the input to the tank, driven by a tank stat so it only heats the buffer to the required temperature. Normal "1 pipe" system bypass when the 2 port is closed.

You don't need to go "off grid" Just do as I am doing and fit your own system. It does mean anything you export you do not get paid for, so just do all you can to self use as much as possible. That will almost certainly mean battery storage at some future date.

So the TOP is open (i.e nothing to fix to) Are BOTH ends attached to something, or is one end floating with nothing to fix to?

I would be building that of 4 by 2 minimum with 2 straight runs across the top. Might also line one side with OSB before the plasterboard.

Photo of the manifold so we can understand which valve was the issue?

That sounds like a good plan. You will need a header tank would that go in the loft or just above the cylinder?

Well I now have the Unistrut. Could not better £24 per 6M length locally. Transporting that on the roof of the car was interesting. Good job the cheapest supplier was also the closest, and has a handy back road route so I could drive slowly without being a nuisance.

What do the flow meters show? They should show water is actually flowing through all the loops. If return temp = supply temp then don't discount the slab being up to full temperature.

This is just "politically correct" nonsense. So you want to fill the kitchen sink with water to do your washing up. What will a flow restrictor do to "save water"? It will just irritate you as it takes longer to fill the bowl.

.... And why are some white, and some grey? What is the difference apart from the colour?

I have hit a snag. When I chased the ebay supplier about the non arrival of my Unistrut, they replied saying it would cost £200 to deliver it here so have cancelled the order. I have been phoning around and the cheapest I can find it locally is £24 per 6 metre length (compared to just a shade over £20 from ebay) I guess I will have to stump up for that.

I had forgotten about brick built garages. Mine is all timber hence the 2 layers of fireline on the walls as well.

I prefer a switch fuse to feed the submain to the house CU. An do everything you can to find a route for the cable that does not trigger a need for RCD protection, even if that means SWA for the feed to the house CU