PeterW

So the RHI can be done and then an Immersun added to any “spare” immersion. If it’s not wired in then it’s irrelevant when he does the calculations ....

Just the same principle that you apply to balancing radiators. Flow control valves on each duct battery and flow valves would help too. Could even use a 2 port UFH manifold but you would need to make sure you insulate the pipework well to stop condensation.

6:1 sand cement will do it. Just lay tiles straight onto the heater element in adhesive.

Yes - there will be enough moisture in the sand for the cement to go off. Makes it easier to level this way.

200/250/300 all share the same diameter base at 580mm - as long as you have the height (1120/1330/1650) then there is no limitation I can see. Once you go to 400 then the 710mm diameter is usually the limiting factor about getting them through doorways. The other consideration is the expansion tank that will be 10% of the tank volume - on a 500 litre this will be a floor standing 50 litre tank which is pretty substantial.

@Onoff1/2” BSP according to this which would match up with your dimensions as it’s 20.9mm and 14 TPI

7/8 14 UNF..??

Does the farm have its own meters..? If so, lay a pipe to within 1m and get a “new” connection from the main to the end of your supply on a new meter.

Sorry that was to the farm supply. If you want to connect to SW then they would need to confirm what they needed.

32mm MDPE is about £1m from Pipestock for a 150mm reel. You need to be able to dig down to min 850mm if it’s farmland or you could use a drag mole if you can get a friendly farmer. Edited to add ... drag mole, mole plough, pipe mole, subsoiler.. all the same thing to me !!

you can just use sharp sand and a DPM under them, or a dry sharp sand and cement mix to level the holes. Then the tile backer board on the top.

Ok that’s fine. It is 20mm MDPE by the looks of it but I would measure to be sure. If you can isolate the mains then just cut the pipe with a decent very sharp Stanley knife, and insert a couple of pipe stiffeners and an MDPE tee. You’ll need to find a short section of pipe to insert into the tee, then use a converter to 15mm and normal pipe from that point onward. Don’t forget to put an internal isolator prior to the outside tap in case of freezing or leaks.

Yep only where the pipe has to come into the cupboard.

I use the Talon pipe covers to go through cabinets whether it’s back or sides - the 22mm ones also line holes nicely with an offcut of pipe where you want to neatly run cables. Just mitrebond both sides

£16-24/kg from where I have seen it. Colour saturation seems to be the drawback but if you’re not seeing it then that shouldn’t be an issue

Is there any insulation in that make up of the floor ..? If not, UFH mats will be a waste of time as it will just heat the concrete.

actually that’s fine so far - he has run the cloak up the chimney and brought the underfelt behind it, then will fit the steps over the top. Only thing I would do slightly differently is create a hidden gutter toward the chimney with a batten but that looks fine so far. If he was to finish it with a strip of flashband that would be a different story .!!

First off that’s 20mm or 25mm MDPE, and it’s not clear which “side” of the meter it is ..? Are you saying the meter is after this connection and then there is a feed to the house ..? If so, that pipe is your supply pipe and you can’t tee into it as it would be unmetered water. You need to confirm that first and then can decide what to tee into.

Inch per yard is 1:36 which is fine

Legionella in domestic systems is extremely unlikely as it needs air to breed - and a UVC is a sealed system. There are no known reported cases of it in a domestic water system. Even if it was required, it needs 8Kw to heat 400 litres from 48-65c. Using an immersion heater that is 2.5 hours, or about 18p on E7 twice a month. £5 per year.

You can buy one from Amazon for change of £20.... got to ask, is it really worth making one .?!

Stud or solid wall..? Cut the plasterboard off the wall where you want to make the run and you’ve gained 12-15mm

He would but she’s at the opticians ...

... and ... For an ASHP system, minimum spec regardless I go for is 300 litre and then usually 400 litre if it will fit. The tank recovery time of an ASHP driven UVC is more than double that of a gas or oil boiler so I would just go with a bigger tank and insulate the tank cupboard and pipework to reduce losses.

You’re in good company ..!! You should ask @pocster and @Onoff for their opinions on how to do it as they have extensive experience ..!