Nickfromwales

Firstly, ref the G3 annual inspection. Ive yet to receive the 'bumf' from the production model 3rdGen SA units as of yet, so cannot comment on the ongoing / routine maintenance of them, but from my PoV its minimal, and maybe even just a DIY checklist / record will suffice. @AndyT ? 3 couples aka 6 guests having 'adequate ( 10 mins @ 38oC ) showers' would need a fully charged 5kw SAPV for each couple. I know from direct experience that the SAPV when fully recharged will give 40+oC DHW flow for at least 26 minutes before dropping off to unusable heat levels, which is why Im quoting the SAPV, just fort scale. Thats on an estimated flow of around 9/10 litres per minute. So 2 x 10 minute showers at 10LPM ( so an instantaneous delivery of 200L of bathing temp, or higher, water ) needs roughly 5kw of SA capacity. In reality it'll probably be less, but you should always allow headroom. So, with that capacity in mind, you'll actually need the 3rdGen Dual port SA units, and for failsafe id recommend having the units with electrical immersions in them ( so if the ASHP ever fails you can still heat hot water ). Those dual port units take non-potable ASHP water in one 'side' and discharge potable DHW via the second of the dual ports, so the same unit hydraulically separates the two bodies of water, but they're 'connected' thermally. Eg the input can be heating the cells whilst the other 'side' is discharging and if say 2kw is being drawn and 3kw is being inputted then the cells will recharge at the same time as they discharge heat. For say a 9kw unit, the whole 9kw can be recharged by one pair of ports, and the whole 9kw can then be consumed by the second ports ( so a dual port SA isnt looked upon to be 4.5kw to one and 4.5kw to the other if that makes sense? ). Another benefit of this is the connections are 22mm, so an electrically heated SA DP can be used solely for DHW with cold mains going into one side of each port ( 2 x 22mm inlets ) and then be paralleled through the SA to give a combined ouput of the equivalent of a 44mm pipe flow rate. Therefore its safe to say these can be configured to deliver masses of instant DHW with flow rates of 30 - 40 litres per min achieved with ease ( so 3 good showers running simultaneously with ease plus a bit of room to draw off for a kitchen sink tap / other at the same time too ). That would obviously be dependant on the cold mains being sufficient to deliver such high flow rates, but easily achieved with a correctly sized cold mains accumulator. All this can also easily be achieved by a large HP UVC just then you have the annual servicing and inspections, which is a reasonably high outgoing over the life of the UVC ( as a good stainless steel UVC should outlive you ). The 9kw sunamp units are about the size of a slimline dishwasher so will fit under a kitchen / utility worktop too. An equivalent UVC would stand about 1600 - 1800mm heigh, and be about 600mm wide.

Tell the tenant to enjoy life, and to worry about things when they break, not if theyll break.

Just blows my mind how they even think of this stuff. Where would we be without clever sods eh? Now wheres my blow lamp?

@Onoff Pretty much yes to everything above. Those steel brackets laying flat, they have soft edges do they ? If not, get something between them and the UFH pipes for Justin.

Wikipedia quote : " Chilblains can be reduced by keeping the feet and hands warm in cold weather, and avoiding extreme temperature change " Am I missing something ?

Oops. Just realised we should chat about this here as we're veering off topic !

Can I ask why you don't want UFH ?

I'm currently spec'ing two installs exactly as you've described. I'm doubling up first as last though as a 'single box solution' offers zero redundancy. I'd say save the money of ducting and pulling insulated ASHP pipework ( not cheap stuff to fit and then not use ) and look at keeping sufficient redundant space for a second Sunamp unit . These struggle a bit first getting the house to ambient, but after that they should perform exceptionally well, for as 'passive standard' usually means little and often for space heating and a correctly sized bulk for chunks of DHW. The good thing about the 3rd gen units is the near linear input of energy, e.g. 3kw of electricity input to a 9kw unit needs only ~3 hours to fully recover from a FULLY discharged state. Best to do as I have and design in some redundancy so you can cope with guest / high use of DHW. ( Space heating is a mere burp as far as these are concerned so focus closely on DHW capacity ). The 3g units have two pairs of 'flow and return' connections ( 2 x heat exchangers ) so space heating ( not potable ) and DHW ( potable ) can both be drawn from the same unit but always remain hydraulically separated. Another good point to make is that either heat exchanger can consume the entire stored energy of the unit, so a 9 kw unit with 2 heat exchangers doesn't offer 2 x 4.5kw 'sides', it can give all 9kw to the space heating HE OR all 9kw to the DHW HE. Tidy . As it has no internal pumps and controls etc, compared to the quite complex SAPV unit, you can inject heat energy near linear to consumption, which makes these a very versatile solution. Im suitably impressed so far, and Andys advice to run one unit and see how it goes is pretty much the benchmark you shouid observe. There is little useful case study to date so seeking advice is unfortunately the only measure you can practically observe.

Thanks for updating .

Check with the neighbours as they may affect them.

Me too. . Better to read and ask than pay and regret. Keep reading. It's free....but priceless. .

Do not do that. The heat won't transfer but the smoke will. MVHR flow rates don't lend themselves to transferring heat about. @JSHarris had elaborated on this more than once, so read and evaluate.....it's all here if you ask or dig .

To have a stove with a boiler you'll need a whopper of a TS ( thermal store ). You'll need a lot of additional heating / plumbing / control paraphernalia which will cost much more to buy, install and maintain. You'll also need a heat leak ( dump ) radiator too, unless it's not a 'solid' fuel burner. Have 'the chat' and see if a WBS ( wood burning stove ) that doesn't heat water, will suffice? Anyhoo. Gas is a box-ticker. Easy, neat and simple. If your dead sure gas-is-a-coming-to-them-there-parts then I'd seriously consider it, just because getting an ASHP fitted may be difficult, but getting it repaired / maintained may be even harder to achieve. ( I just realised you have a hot press not an airing cupboard ). Most plumbers can fit a gas boiler so you'll find much more support available for that. FYI if you go for a Vaillant boiler then converting between LPG and Natural Gas is literally a 5 minute job with a flat blade screwdriver and a U-gauge. No stripping of the boiler / changing of jets etc . Other manufacturers may do similar but I know the Vaillant does. I fit mostly Baxi or Vaillant. Great appliances.

Some basic reasonably priced controls that don't operate the garden sprinklers via thumbprint or voice recognition . They call them programmable room thermostats and they start from as little as £60. .

Cranking it up to get a good chunk of hot water is the only thing you can do at the moment because the boiler can't shift heat into the TS quick enough at the moment, because of that PHE and the TMV on the TS return ( prob ) being set wrong or failed altogether. If that has failed or is set wrong then even to get DHW the whole TS will be trying to heat up, rather than just the top 1/3rd. Pointless fretting as it'll only get better with an overhaul.

It won't be . When set up properly it'll just be coming on, topping up the top of the TS, and then knocking back off until needed again. That would be 'summer mode' where you don't want to run heating. If you want heating then the boiler must be allowed to run to offset whatever heat is being lost from the house. It will still only heat what is necessary, it's just set up terribly at the moment, and when it's doing things it's the wrong things.

Holy ? Was the ASHP 24 carat gold plated, and decorated with unicorn feathers? I think you need a serious look again over this lot as you've obviously been given some duff info here. Seems an ASHP would be much cheaper for space heating and DHW preheat, Scrap the "intelligent heating controls" and put that money towards PV. Why the multifuel stove? If you want a stove then just have a gas ( LPG ) / electric dial fuel stove / range. That would save a lot of cost and complexity IMO, so more £££'s to go towards the PV . Do you have any quotes or designs you can upload ? Please remove any sensitive information first My 2 cents:- ASHP. HP UVC. Buffer tank and DHW pre heat. Preheat optional as you can live without it. Down to available plant room space for the two cylinders. PV into both / and ASHP to reinforce ( reduce ) grid consumption. LPG cooking if you don't like electric. Job done and cheap as chips to run.

If your really that concerned then exactly how much 'bounce' is there? Are you mistaking the layers compressing slightly underfoot for bounce? As I know you pretty well by now, a solution. Get a 4x2 cut it 300mm short of ceiling height. Drill the end to take some 10mm SS threaded bar. Use that with a couple of nuts andxwashers to create an 'acro prop' and sit the threaded bar on a bit of SS flat bar. Use that, pushing from the ceiling down, gently, to take any slack out during screening and grind the threaded bar off after the screed is dry.

That lot won't budge a mm. . The two brackets laying flat over the membrane, I'd stick a couple of short stainless bolts through them to make pins that the screed will hold and that's that. I take it you've not looked at tanking properly yet . The areas you fear may split are all junctions. The tanking kit comes with long strips like band-aids which stretch and flex with the wall / floor 'fault lines' so such a problem cannot occur. The tanking solution is like rubber when it's cured rather than brittle like paint, hence why your using it. Just put a good few layers on, allowing to dry in between, and it'll be bombproof. . Have you opened the tanking kit yet? Or haven't you bought it yet?

The chase isn't fun if you catch them .

Inevitable !

Better than expecting a child

You wouldn't possibly be having a Sunamp PV if you have an ASHP . You'd maybe instead be going for a Sunamp dual port that takes in wet heat as well as PV based electricity. That way you'd maximise the efficiency of feeding it with heat energy when the PV isn't up to it. Far less parts and complexity too, that all said bearing in mind that Jeremy has the flagship model and the available range of Sunamp units has grown significantly of late.