CurvedHalo

Would you suggest that this system of 13 outlets/13 valves/13 pipes is the correct correct approach? For high pressure, in an unvented cylinder system?

@SteamyTea sounds like you're not an advocate of tank in tank. So separating the two tanks for you is a better solution then?

I've been reading about air-source-heat-pumps, and that a new cylinder would need to be fitted which has an element with a larger surface area (I guess as the water is coming at a much lower temp in the ASHP vs a conventional boiler). I also have read about the use of 'tank-in-tank' cylinders, where domestic water is stored at a high temperature, but much lower volume, and then central heating (UFH) water is stored a larger volumes but much lower-temperature. Does anyone have any experience of these? Are they beneficial? Does this mean the flow/return to the UFH mixer is now independent to the DHW? Finally, hypothetically, in a system using solar panels, would it be better to use the generated electricity to heat the water in the cylinder directly using an eddi? or is it better to store this, and use the ASHP to heat the water from stored electricity I have generated? Thanks!

Hi all, sorry if I'm repeating other questions, I can't seem to find anyone asking this same thing? I'm doing a self-build and I'm currently at the point of fitting my domestic pipes. I'm using point-to-point plumbing, so plastic pex. Q1: My plumber says that they usually fit the pipes directly to the subfloor/slab, and then cut insulation around it, and screed on top etc. While I guess this works for cold water, would this have a negative impact on the DHW, as it's essentially outside the thermal envelope? I know we could use pre-insulated pipe, but I just wanted to know about this. Q2: I have always had problems with leaks in copper pipes buried under the ground, which is why I've chosen this point-to-point approach, so no joints are buried. However, my first question is - Is there a risk of this pipe rubbing as it expands/contracts, and therefore leaking anyway? Are there any mitigating factors I can do to reduce this? - Is there any benefit in burying this pipe within a conduit so I can replace down the line if I ever need to? Q3: as a last point.. in the plumbers design, he is proposing to take one pipe from the manifold to the bathroom's toilet, and one to the shower, and tee off this to supply the bath and sink as well, saying that the connections will all be above-ground, and the likelihood of any of these 3 consuming water at the same time is next to zero. Is this common practice? I was under the assumption that every draw off point would receive it's own supply? Sorry if this is really basic, I just want to get my head around some of these decisions and most people round my are just use trunk and branch copper piping.