Nickfromwales

@canalsiderenovation Don't run back into the arms of these dickheads out of desperation. They've not done a good job here, just perpetuated their revenue stream and kept themselves in business. As part of their visit, they should have diagnosed, not just said "fit a bunch of new stuff". FFS. At the ABSOLUTE minimum, they should have asked to charge you for an hours labour, to check the red vessel pre-charge pressure, to ascertain what is going wrong. The system is too young to have major faults, this is a mountain being made out of a molehill IMHO. The issue(s) is NOT diagnosed well enough yet, so we need to know if the discharged water was warm or hot, and if the heating blew this off or the UVC did. Without this info you, and the aforementioned dickheads, are just flying blind. Leave the hot water on via the ashp and use your showers, you'll be fine for the immediate. Turn off the Solic, even though excess PV at this time of year is negligible anyways, which will reduce the magnitude of the situation.

Just put a 4th RCBO in the aux CU and run it to a double socket so you can plug stuff in downstream. Easier and cheaper to get this done in one hit if you’re getting a sparky out.

I thought the Shelly’s could be bought with switching capacity for direct connection to the immersion.

3 channels of Shelly’s is ample control and completely flexible.

Yes And yes. MCB’s aren’t usually used these days, as RCBOS offer better protection.

Simple fail-safe is to bridge L&N from the Shelly in(s) & out(s) in a local 20a DP switch (the type normally used to turn an immersion on / off anyways) and no heads go on any spikes If we do an UVC in an attic, I always fit the 20a switch in the living area somewhere, with a neon, and then the lady of the house just pokes that with her finger vs your left eyeball.

It’s down to the length of the cable, for voltage drop, and things like grouping factors, if run in a bunch with other cables quite tightly packed aka “contained” (trunking and conduit etc). You can hopefully run a 50a MCB in the primary CU and then fit 3x 16a RCBO’s in a secondary CU in the attic. Those each feed a Shelly, and then you use heat resistant flex from Shelly > immersion. You should use bootlace ferrules for the flex’s Link to make the best possible connections. How often do you think all 3 will be running? This is an all electric house with no heat pump? You can’t do this because of the high rating of the supply breaker. 32a max to a single socket or double socket or fused spur, fed locally via 4mm2 radial or 2.5mm2 ring. For eg, I swapped my electric shower for a thermostatic unit when I fitted a gas combi. The 40a MCB then feeding the 10mm2 cable got reduced to 32a (RCBO) and a BFO (60a) junction box went on the end of the 10mm2 cable where I made a new utility area. I came out of the JB with 2.5mm2 as a ring main, picking up 2x 1G sockets for the washer and the drier, and another for the boiler spur. You have to reduced the available current locally, or at source, to match the lowest current carrying cable in the chain; so you can’t have a 40/50a breaker directly feeding sockets or spurs.

He may have used a pump-up pressure bottle to inject, vs drain down and fill via a towel rad / other. Service guys don't like getting wet.......

1. Just start ringing local spreads tbh. 2. I'm no fan of taping and jointing, other than in a non-domestic setting. Plaster is the way to get the best finish, subject to the spread not being shite. Scotland folk often say that plastering is not common practice, so you may have to ring around a bit / lot. 3. Don't screw through cables or pipes! Select the correct length screws for each room.

Flexible tile adhesive. Always important to decontaminate the underside of the tray as they come covered in dust and mould release agents and so forth. I get a cotton dishcloth (old school ones are best) and use a bit of the tile adhesive made up a bit wetter and scour the underside of the tray until you see the adhesive wanting to stay on it. Then butter it a bit and you know it's going to stay put.

Ok. You’ll want to be able to push the tray side to side, lengthways, by 5mm (so 10mm of wiggle room), and to be able to have it 5mm away from the opposing wall. This will allow you to get the tray in, and to then be able to load all the gaps with clear CT1. You then mask the top of the tray on the 3 sides, frog tape or pvc electrical tape, and once loaded you push the tray towards the shower head end, and then back against the long wall, displacing the excess. Use (lots and lots) of cheap wet wipes to clean up the excess and then fill up the gap on the far end. Tool this into shape with a plastic packer and then peel off the masking tape. BINGO. Search wetroom and tanking on here and shower room for more info. And this may be a good read. Tanking the shower makes it bombproof. Been doing high end bathrooms for over 30 years and zero failures.

This person should have given you the correct solution at the outset, as your principal designer!! Another shining example of the differing levels of competency that are out there.

Only an option if you get permission to discharge storm water into the foul network aka ‘combined sewer’, otherwise you could be in a spot of bother if an issue ever occurs downstream.

Can you not use slabs? https://www.insulationuk.co.uk/products/150mm-superglass-superwall-32-cavity-wall-batt

You never asked for your 1hr free consultancy