Nickfromwales

In heating mode you will never get anywhere near to using all of the 24kW unless you have the house freezing cold and want to heat it to 22oC ASAP. Nominal heat from a wall mounted boiler would be 12-14kW to heating ( max ) and then whatever you have for DHW will dictate how fast the cylinder can reheat ( aka "recovery" time ). To be able to heat the cylinder and run the heating simultaneously it could be beneficial to go up to the 28kW as the minimum heat output ( maximum modulation ) will be pretty much the same, or you could stick with the 24kW and go W-plan ( domestic hot water priority ) which would allow either the heating OR the DHW only, and never the two together. The biggest issue you'll have here is running the UFH separately from the radiators. As these are two completely different beasts the plumber would normally specify a room stat for each UFH zone, with a 2-port zone valve shutting the UFH on / off respectively which then islands the UFH from the rest of the system. The cylinder and rads would also have 2 port zone valves that isolate them in line with heating and hot water demand. If the UFH is running and nothing else, then the boiler will short cycle. To deal with that, you would need a 50L wall mounted / floor mounted buffer tank across the flow and return to the UFH manifold AFTER the UFH zone valve ( so it does not act as a bypass when the UFH is off and heat unnecessarily ). This is multi-faceted as always! Q: If you have 2 electric showers, and only one that uses DHW, then IMHO it is a waste of time and money to fit a system boiler and cylinder. Why don't you just fit a high flow combi such as a Vaillant 938? That will exceed you DHW needs for sure and then you don't need a lifetime of annual G3 service callouts for the UVC.

Only usually required with electric UFH / UTH

How thick will the screed be? It’s a can of worms putting a thin layer over existing outdoors. Water ingress + frost = ?

My screed guy will only go less than the nominal if bonding. Then he will only go down to 25mm minimum. From there I use SLC to feather down to nothing where slopes diminished. 25mm on last job, with UFH, down over 10 years, tiled, one tile cracked ( but tiler was shit and prob didn’t use a mat ( or a flexible adhesive )) I’ll bet.

Not big enough. Go poke a bit of 3-core 1mm down the inside of a 16mm pipe and see what you’ve got to play with. You’d not get a draw tape and a flex down that boyo ? let alone 2 cables for 2 stats.

Connect future pipe to the ports now, run it through the existing floor to a point where you can excavate a little to expose the ends, and just cap end them for the immediate. Use straight connectors to join back onto the pipes in the floor at a later date. FYI the fittings for 16mm UFH pipe are ridiculously good quality and I have put plenty of the joints in to repair damaged pipes / alter previously installed jobs where I've had to correct, etc etc, and they just do not leak. Put 9mm foam insulation onto these runs to preserve the heat in the flow pipes, and then a bit on the end of the return too, where the cap ends are, to keep the pipe and fitting in top condition. You do NOT want to screed these in and then damage them when you come to dig them out at a later date Don't forget to run a cable in a conduit to the same point also to extend and connect to the additional room thermostat(s) in the new extension.

Quote from DAB's website:- "The ESYBOX MINI 3 cannot be connected directly to the mains water supply, it must be connected to a suitable break tank." In some areas, putting a vacuum deficit onto the cold mains is a prosecutable offence....

Are you happy with the work / timekeeping etc?

Plus, when you’ve paid your money, the Wunda system will actually work. Advantageous in ones pursuit of warmth ?

Nope. The mains ‘passes’ the accumulator and goes direct to the outlet. The potential stored in the accumulator exits the vessel to fortify flow. When the outlet closes, mains starts to recharge the accumulator again. Mains will never enter the accumulator until it’s own potential is lesser than the stored potential. Trust me, this works very well. You just need to size the accumulator for your specific requirements. For the rotund Welsh tenor, Paul Potts, we fitted 2x 500’s to suit the demand. They went in the garage with a 500L UVC. With the job I mention above with the electric showers I fitted a 300L in the attic.

Spot on.

In a nutshell, yes. The only issue with an HRC is that any serviced DHW runs, plus the HRC return pipework, need to be super well insulated to stave off heat loss in the connective pipework. With a modern, well insulated UVC you should not really have to worry about the extra bit of heating input from the boiler when using any pump to stratify, as these lose very little heat per 24hrs tbh. They are designed to be 'fully' heated during normal ( vertical ) service plus when 'stirred', the horizontal units will give much closer to their stated useful DHW capacity. See page 18 HERE If you don't want to install a full HRC, then just fit the stratification pump and power it off the switched live of the DHW zone valve ( so that only runs during a reheat cycle thus filling the UVC to the max with heat energy ). Just remember to insulate the pump and pipework as much / best as possible. There are EPS pump body jackets available to make that easier / more practical.

Fresh air, definitely. Just commissioned one almost exactly like this, and fresh went into the dining and vaulted area feeding back towards the kitchen. This ensured the glazed area would never get 'stuffy' and the smells from cooking would never be attracted towards these areas. The design should be adapted to have the "UNIT2" fresh nearest the vaulted area moved to be in the vaulted area, with both of those spaces then having a single ceiling valve which has 2x ducts to each giving fresh air in. NOTE: extract will shift bugger all heat from that glazed aspect Trickle rates just do not shift anywhere near enough air to even scratch the surface.

Nah, there's only space for one person in his life Him.

Taxi for Nick please. I’ll moderate myself

Better make it 6

Needs paying up front. I’ll pm you my…… I mean his bank details now.

I’ll have a quick browse for a product capable of taking up the amount of slack that’s expected with you ?. May need something industrial ?

Illbruck stuff is good. Goes of tough as old boots with minimal expansion / excess.

Depends if you have PV and want to ‘stir’ the tank when diversion is happening, as, tbh, that’s when I’d recommend fitting the pump to aid stratification. HRC pump will sort that if not ?

That's the best option, but would need to be very robust, including a rights of access to the 3rd party ground that the pipe lays in for repair / replacement etc. In terms of pressure and flow, if this is a tee'd supply and the run is huge back to the 'street' then you would need to be able to demonstrate that you are not going to starve the existing dwelling of it's own flow and pressure. That can be mitigated by you installing accumulators, prob 2 or 3x 500L, so you can always run taps off your own 'artificial cold mains'. That would stops arguments when you and the seller both jump in the shower at 07:30 and the flow runs to a dribble. Any chance you can get statistics off the sellers supply atm? Would be critical data before advising any further on tee'ing into that supply. Could be a game changer in simplicity and mean owing the dwelling asap.

Yes, you're right. Was just thinking of a completed system producing water fit for consumption, but, for the purposes of proving, just the pump needs dropping in and samples taken to prove it can be made potable by treatment and volume available. Good point

I mean the equipment downstream of the borehole. Accumulators, filters, expansion vessels and the what-not eg a plant room / space which is populated for the purposes of the investigatory works, which then is not in a convenient place when you come to renovate.

Nu-Heat = ?. Go with Wunda.

External foam is all superfluous so get rid of as necessary