Nickfromwales

Good idea. Only downfall is you have to have a bit more waste as you need a factory capped coil for every run. Having them 'gas' pressurised during installation and then pressurising with a gauge on the manifold prior to / during / after the concrete pour is the gold standard. You'll know if you had issues during installation as a damaged loop wouldn't give you the steam-train whooooosh when you cut each loop to fit the manifold.

Yup. That’s why they have very fine pitched threads, so lots of bite for very little torque.

Over what distance? This is just a short branch.

"We'd just like to thank everyone for watching tonight's show, and please remember to tune in....same time next week. Goodnight!". ?

Fresh disinfected water will be passing this, so I would not worry. The metabolism says the risk is minute.

I always CT1 here as the casting of porcelain is often imperfect, as is often the tile ( especially where the pan traverses a grout line and there is a distinct wobble ). Cutting through CT1 in the event of a doomsday issue is a few minutes work. CT1 Multisolve can be used to break down and remove residual product, and clean up before re-installing. Hearing a 'dry' pan grating against a tile whilst you tighten, and then do the first test arse-fit, is bloody daunting to say the least. And the gasket should be banned from existence !!!!!! Do not fit, it's like a bloody slip membrane and stands the pan off an extra few mm's which means more silicone on the upper rear edge of the pan.?

Tell him to say "no" to drugs An UVC will have 22mm pipework and will happily connect to a 15mm cold mains. The discipline you need to observe is taking the 22mm cold supply all the way from the UVC multi-block ALL the way back to the 15mm cold stopcock. Reducing the resistance that the cold mains has to suffer before getting to your outlets is the critical thing to observe. You really need a plumber who has done a few ( lots ) of UVC installs, as the difference between plumber 1 and plumber 2 can be night and day. If you wish to retain the existing combi for money saving measures ( as long as it is in A1 serviceable condition ) then just have the hot outlet connected to the kitchen sink, and then use the heating circuit for heating CH and the UVC. That will work just fine. Do NOT connect the combi hot output to a shower, as whilst the shower is running ( the combi is in DHW priority mode ) zero heat will go to either CH or UVC. Flow rate and static pressure of cold mains needs reporting here before ANY advice can be given. You could get away with a Vaillant 938 and an accumulator, but we also need to know how many people living there, when they shower / bath / how often and more. INFO PLEASE!

Must be a real problem holding cutlery lol

No, as room 2 looks like it will overheat if serviced by the loops feeding from / responding to the kitchen thermostat. Room 3 the same? What are rooms 4, 5, & 6? You should have that space serviced separately, and all the flow and returns to the kitchen should be lagged ( insulated ) to prevent unwanted heat loss into room 2, same elsewhere eg where the pipe runs are condensed and especially where they serve a different room. With 50mm screed i would want room stats and deicated zones throughout and to use a stat with a very good hysteresis, say 0.5oC or less. Is this a 'passive' build? eg tested as air-tight and super insulated? I would go for 120mm centres with 50mm of liquid as that's the worst type of UFH emitter you can get imho. Increased CSA and increased water volume / wider spread of pipes will lend itself to the lowest flow temp possible, but that will be dictated by the W/m2 that the dwelling requires to maintain a comfortable ambient internal temp vs outside temp. Serpentine layout as per your drawing is carp, go reverse / inverted and then you only have U-turns at the centre of each loop

About 11mm, so all good.

+1. I've been saying this to people for years. Still get stubborn assholes who say "it's OK".......it's not. Copper into compression and a hep fitting onto the copper each and every time = bombproof.

Jesus. There's a special place in hell for you lot Just over hand tight, and don't go mad. It's the rubber seal that stops water leaking, the threads just keep the rubber seal where it needs to be. And, deep breath, a bit of lube will stop the rubber getting FUBAR'd.

Iirc, the UFH pipes from Wunda come Pre-pressurised with air / gas and the ends plugged sealed and factory tight judging by one I cut ( without knowing they’d started doing this, so subsequently nearly ? myself ), it’s at quite high pressure too. You’d 100% know you’d damaged it, but would the person who’s damaged it tell you? Also, a tiny puncture may not be notable so maybe not the immaculate solution. A pressure gauge is the only true way of knowing that the integrity has not been compromised. Water is not necessary, but it’s 500 times quicker to find a leak with water squirting out vs using leak detecting fluid with air.

Are the pump isolation valves all 100% open? Close them fully, then open them fully to be completely sure.

Typically the pump should be pulling on the outlet of the mixing valve, not pumping into one of the inlets. Not how I'd have set this up, and I'd be surprised if that's working as intended ( however that is supposed / intended to work !?! ). My guess is that the mixing valve is installed incorrectly ( upside down ) as the direction of flow through it appears to be wrong vs the drawing at the outset of this thread.

The inspection branch would be internal access as you’ll be T’ing in there, but you could get away with 2x inspection bends outside if the branch is going to be inaccessible after completion.

Yes. Been done a hundred times or more. Make the bend on the turn at the rear of the WC an inspection bend for belt n braces. Likewise with the branch indoors, eg buy an inspection branch.

You can take risks for yourself, but a 3rd party cannot do that to you, so regs need following. If that comes down, you wouldn’t want to be in the room underneath it when it does.

Just chuck some chrome compression pipes onto a standard concentric valve ? Set the valve a bit higher to allow the plumbing to do its thing and seal up where necessary. Or, can you fit a TMV on the pipework to the bathroom? Does it go underneath and you can just chop one in there? You want to intercept the plumbing before the basin and shower, but not the kitchen sink, ideally.

Caravan things are out there a plenty. https://www.ebay.co.uk/itm/164643835176 One with 45mm centres. I’m sure a bit more googling will turn something up.

If there is free-draining material behind the retaining wall then I see no issues whatsoever. The penetrations will need ‘grouting’ to make them watertight but as long as that is executed meticulously you should have no problems with that proposed run IMO.

https://forum.buildhub.org.uk/topic/3020-combimate-water-softener—opinions/

You can use a timer + AA pump Each instance is individual to occupancy / usage. No right or wrong here. A loop in 10mm for the HRC ( hot return circuit ) is what I was referring to above, and deffo not suitable for feeding 2 or 3 basins, unless you do away with an NRV and allow DHW to flow down each direction to the outlets ( a bit like an electrical ring main ) but that’s quite unorthodox and wouldn’t be something I did by design, more of a “work-with-what-you-got” solution. The advice and disciplines change for folk who are doing / have radial plumbing vs those who have series plumbing. With the latter, you may as well just do a series loop in 10mm and T off for each HRC serviced outlet accordingly. Advice also changes again for new installs by design vs retro fitting something to cure problematic dead legs. No one ‘standard’ solution.

Drop the nut and plastic washer, big bead of CT1, and wind it back up. Put loads on, and clean the excess off with wipes. Don’t let it go up as far as the slots for the overflow runoff.

+1