JohnMo

For others reading this. If your system boiler has opentherm. The EPH unit referenced to by @SimonD (up thread) will make your system boiler supply different flow temps via opentherm, so your system becomes priority domestic hot water when using 2x 2 port valves.

You need ventilation in all wetrooms to comply with building regs, a WC is a wetroom, so needs a fan. Specify wetroom windows without trickle vents. This follows the rules when you have continuous mechanical ventilation. Link: https://www.labc.co.uk/news/replacement-windows-and-trickle-vents 2) If the dwelling has continuous mechanical extract ventilation, installing trickle vents in any replacement windows which are not in wet rooms, with a minimum equivalent area of 4000mm2 in each habitable room

I would Delete all dedicated hall loops, spread all pipes transitioning through halls out across floor. Come down to one manifold only. Do 200mm centres generally, but keep bathrooms at 150mm or below. Maybe even 250mm in bedrooms, but just do a single loop in each bedroom. If you locate the manifold in utility, you wouldn't need a loop in there either, just spread pipes across the floor. This is our floor, loose 300mm centres. Kitchen is generally 0.5 Deg cooler than lounge, bedrooms are a degree to 1.5 cooler than rest of house with doors closed. Open doors and the rooms even out over a hour or so.

If you read the manufacturers instructions, they will mist likely tell you to add a condensate drain at any low points. If not I pretty sure building regs will. A 5 second search https://www.google.com/search?q=150mm+condensation+trap&oq=150mm+condensate&gs_lcrp=EgZjaHJvbWUqCggBEAAYChgWGB4yBggAEEUYOTIKCAEQABgKGBYYHjINCAIQABiGAxiABBiKBTINCAMQABiGAxiABBiKBTINCAQQABiGAxiABBiKBTIKCAUQABiiBBiJBTIKCAYQABiABBiiBDIKCAcQABiABBiiBDIKCAgQABiABBiiBDIHCAkQABjvBTIHCAoQIRiPAjIHCAsQIRiPAtIBCTExNjk4ajBqN6gCD7ACAfEF5ygzgMLm-90&client=ms-android-oneplus-terr2-rso3&sourceid=chrome-mobile&ie=UTF-8

I would skip the thermal store, if you need 45 degs, heating the TS to 60 degs would hold 35kWh, so a small dent in your 110kWh. Also be a rubbish CoP doing 60 Deg and the ASHP may be defrost hell when you most it. An unvented cylinder for DHW, and an open system for heating running WC. Put a 3 port diverter between heating and cylinder so they run different temperatures.

We have a 4G one up and running and it looks like this. VID20251124192811.mp4 If they haven't fully commissioned call you supplier, to get them back. There is nothing can do on your end by yourself.

I used Epicair for my Ubbink stuff. Pretty good delivery and prices, just about the only company that had stock of anything during COVID, so used them after as well.

I think it's designed to fit the other way round, so a floor rather than a ceiling and then just gets screeded in place.

I found this out a year after I installed mine. PV ultra cable is what you need now

I was thinking "not fit for purpose" it's not a ventilation unit as required by building regulations. So therefore not compliant with BR or manufacturer installation instructions. Several reasons as you have detailed before, recirculation of smells, high humidity etc.

We are a similar size to you with 7 circuits. So there us plenty of room to reduce the number of loops. I wouldn't have dedicated loops on hall and certainly no loops in a pantry. We have one loop per bedroom 3x, 2x in lounge, one loop ensuite, another loop does main bathroom, then does hall area near front door and then kitchen diner. I would simplify to a single manifold - post your design and get it reviewed? Manifold can go anywhere, but you have a lot of pipes (36 at the moment) to bring down the walls, if upstairs, the pipes are likely to need insulation as the area will get very warm, also you will need a deep service void - I would find space central downstairs (airing cupboard) then run flow and return to manifold.

I used a mix of manufacturers to get what I wanted (all 90mm). If an adapter is available or doesn't suit nm it another manufacturer Zehnder etc. Ubbink 90mm duct to Zehnder adaptor

Best way to really exploit Cosy is with a battery. Without it, I would look to program the heat pump off in the expensive store at tea time as a first step. Some only run HP in cheap slots, at elevated flow temp - batch charge floor in 3 periods, but if HP is well sized for house this may not yield a good result, as it cannot output enough energy to satisfy 24 hrs house energy demands in 8 hrs. But a downside if you could, without some sort of look forward (weather forecast) and the energy needs, it's easy to overcharge the house with heat and use excessive energy, that's not needed. You may also get a yo-yo of house temperature. I also tried running at an elevated flow temp during cheap periods and WC the rest of the time, didn't really work for me. The other downside of making the HP run harder, in cheap periods, is of the 2 slots, are when it's the coldest parts of the day, so defrosts are likely and CoP can be rubbish. So low and slow may be cheaper overall. The downside of high outputs, in cheap periods, without careful control, you actually use way more energy that you actually you need. Have a play with settings and see what you get out of it. Would say careful tuning and optimisation of the installed system my yield better results.

For me if the house was on fire and it's a sunny day, would a firefighter be able to make safe the PV array without entering the house. If not, I would add a suitably rated external DC isolator in an accessible position. If the inverter is outside and accessible and has an inbuilt DC isolation switch, you really shouldn't add an additional one, according to the rules. That's my view, may different from others.

Tog values affect flow temp, you really need to get the system up to temperature. Leave for 24hrs and then assess if rooms are not getting hot enough. I would wind the thermostat(s) up to a little warmer than normally set, so it doesn't affect results too much. If all room are getting to temperature job done. If all room are not warm enough trim flow temperature up. If you get to temp really quickly and it overshoots trim temps down a little at a time. If the odd room is too warm decrease flow temperature of loops in that room - opposite in cool rooms.