Nickfromwales

Any good tips as I may well use it on the next wetroom floor?

With the backer / cement board I found plenty of PG sufficed. Pushing the CB back displaces the PG and the gaps keep what they want. Allow a good 24/48 hrs for it to fully cure before cranking the loo back, but given this is @Onoff's bathroom it should be long gone off!

It's ok. He's got lots of spare time on his hands

Put the multitool down and go to the fridge. ??

Two words for that. Dog & shit.

? Basically, no. Being so close to the loo, the flush velocity will be more than sufficient to send U571 to the depths without a clog. . That said, having two tight 90's back to back ( on the horizontal plain ) is not a design that you should aim for when offset / obtuse / acute bends are freely available. I've done the bends back to back where I've had boxing in, but it should be avoided where possible. Even 90o elbows in 110mm soil are 'swept ', ( the internal bore is a continuous sweeping radius ) to a degree, so it's not exactly a sin afaic

You won't get two 90's back to back in that short a space. At 200mm from the back wall to the back of the soil, it's less than a whole pipe width .

What did your plumber do with the unused coil tappings? If they're left open you can get condensation forming inside and that causes corrosion. Not a prob if they're stainless, but if they're copper then they need sealing with a bit of foam / mastic. Don't cap them as there could be expansion issues with the coil heating and cooling the air inside.

+1. Chase the block work around the pipe to get a 45o bend ( double socket ) recessed into the wall and then a single socket 45o bend into that to get you back tight against the wall. 2 x single socket 45's prob won't get you back far enough.

You get them specific to your remit . No such thing as a "standard" TS afaik.

Nah, just what I say when I start the day in 'clean' clothes, and then have to go back home to chuck the boots and combats back on Well, before this got to a point where we assumed anything, and then you acted upon it, I thought it best to chat briefly with the tech guys at Telford to see what can actually be extracted from a X sized buffer tank with regards to DHW uplift via an instantaneous coil of X size. Bigger of both = more and vice versa. So....after a chat and a brew....deep breath...."options" :- On the assumption that, You already will have an ashp installed and working. You already will have a buffer of whatever size installed, according to majority advice and positive feedback here ( against running a HP to Ufh directly in a 'low' energy home ). You will have a reasonably sized Pv array. I have arrived at the following :- The costs of the larger buffer tank, having it fitted with a 4.5m2 DHW uplift coil ( the minimum size that would offer any meaningful yield at low temp but also physically too big to go into any less than a 300L cylinder ), accepting a reduced max flow rate of 18litres per min, ( you may well only have 18litres per min coming in so case specific for that point ), and the additional volume of antifreeze ( plus replacment of the antifreeze every 5 years as it has a limited working life ), make the TS and coil option for DHW uplift very tight, if not plain uneconomical for your expected DHW needs. So, after more head scratching, further tea drinking and procrastinating..... The figures do stack up quite well in favour of going for a small buffer and copying @JSHarris with a plate heat exchanger, but as your expected DHW consumption and flow rates may well be double his, I'd suggest going for a pair of 30kw versions running in parallel to get a combined pipe size input & output of 22mm ( to match the UVC accordingly ). PHE example only PHE's are far better at transferring heat from a wet source than coils, especially when being used at lower temps. I've had to adjust my thinking accordingly for this case, and even so, I still think it's a worthwhile endeavour. Less long term labour of the ASHP = longer life expectancy. Far fewer defrost cycles compared to driving DHW directly from the ASHP at high temp range. Majority of the DHW getting produced at the better CoP rate, ( DHW will be your biggest energy requirement as its needed year round eg also when you have little or no Pv gain ). Smaller buffer tank ( circa 100 litres ) with less loss, size, and reduced antifreeze required. ( thanks @Alphonsox for the example costs, makes it a game changer tbh ). So, to summarise, I'm still thinking of DHW uplift from the ASHP via a buffer, but a smaller buffer and PHE's instead of the coil. That will require a pump and flow switch, ( any PHE will need one ). Still relatively straightforward tbh, and may just provoke me into getting off my arse and looking for a decent plumbing schematic software so I can translate this babble into a working drawing for a / your plumber to follow. Thats the chat I've just had. These cylinders have very low heat transfer rates at low temp, so that type of cylinder would need to be VERY hot in order to do what is suggested in that image . It would also need to be KEPT very hot to do it too .

Antifreeze + inhibitor, a combined product, and its diluted not concentrate. . I've suggested a bigger buffer and to make it a TS to get cold mains uplift from the ashp via a internal DHW coil. The reason for the larger size is to get max yield from the low grade / good CoP in order to return the lowest DHW running costs. Pv to HP when running, and excess diverted to UVC when available. If the HP is running in the winter when pv tails off / stops then DHW will be the biggest consumer of energy, so the idea is to use ~35-38oC HP flow to provide around 3/4 of the DHW energy, rather than use the higher temp / poor, zero or negative CoP direct to the UVC for DHW. I ( have ) stated that the sizing be respective of the property, occupants and expected ( future anticipated ) consumption, and patterns. The coil in a small tank would likely struggle to indirectly transfer the heat from the HP to the DHW uplift coil in such a small vessel, at the rate it could be consumed, so again reinforces my suggestion of a larger buffer ( TS ) . Maybe I'll call Telford and see what the coils can actually do, but my gut says bigger is better here. It's no real extra cost on installation other than twice / three times the volume of antifreeze and a few hundred on the larger tank ( remembering it would have a DHW coil costed in either way ). If we're on the right track I can get some exact details which would allow me to be firmer on the cylinder types, and sizes. Let me get out of these wet clothes and into a dry martini and I'll come back with the outcome . Focker out.

You've been called worse, c'mon

Cattle grid and a BFO draught excluder it is then

A buffer is just a dumb vessel with a coil / tappings, but when you upsize it, add things like a DHW coil and start 'multitasking' with it you'd then refer to it as a TS. ( imo ).

Iirc Telford manufacture for Joule so I'd try direct to Telford first via Trevor at Cylinders2go ( +44 7939 996940 ) and mention the forum and my username. I've gone for the larger TS as it'll negate drawing excess electric from the grid to supplement / top up the UVC temp, with the PV offsetting losses and hopefully giving that essential daily nudge towards 60+oC. That's best perpetuated by not removing too much heat from the UVC in any 24hr period by using low grade heat from the ashp to reinforce the DHW delivery with max CoP. I have not accounted for the UFH loops, but TBH I'd rather see the UVC dropped to 250ltrs before I saw the TS size reduced as heat transfer 'en-mass' from the HP is best derived from not using a cylinder coil to transmit the heat but by heating a larger body of water directly ( so via flow and return tappings on the TS body ). I guess that a 200L TS may suffice, but my worry is about the low grade heat being sapped quicker than the ashp can replenish it. The whole basis of my 'design' is around producing lots of DHW via the ashp at low CoP, rather than supporting it with electricity, with the pv powering the HP and excess going to the UVC.

You can make a 'back drop' chamber but it's a bit yesteryear. I'd just combine flows with smaller local ICs and then join the main run larger IC accordingly. Maybe best to run this past your BCO TBH rather than just steaming ahead .

Yes. Just put two in line with each other or a smaller chamber to take 2 into one before getting to the larger chamber.

How many bathrooms / occupants? Could you get away with a hi-flow combi?

EPS wrapped in a vermin mesh and then a galv / stainless cattle grid atop, bridging the EPS and supported by both cold and warm slabs for load-bearing (driving over ) ? Surely this is quite straightforward to resolve ? What about a thermal break in the heated screed / concrete and then only heating 8/10ths of the garage floor?

External oil combi for the colander, and an ashp with electric + LPG cooking for yourself?

Lol. A TS can come with dry pockets cut into the side, basically a metal tube capped at the water side, and the torpedo of the stat just slides into that for referencing the cylinder temp. I ordered a TS assuming the manufacturer would have provisioned for the cyl stat. They didn't. My fault. One of the spare flow and return trappings would have accommodated that unit and saved me a mountain of grief. Type that in ?

Bugger. I needed one of those a while back for a TS with no stat pocket, but it had a spare return tapping that I could have bushed and inserted that into. I'll bookmark that site, cheers ?

Pm @Barney12, as I believe he 'may be able to help' .