PeterW

Run in Hep2O and insulate - nothing wrong with that. Just make sure it’s more than 50mm from the treads / risers so when the carpet fitter etc slam a few screws in you don’t get a shower ..

Yes you can use 125mm convoluted aluminum duct but make sure you insulate it

Each loop should be adjusted to the correct flow rate to deliver the heating required. If you turn the pumps down and check the flow rates, you may find they are still ok as per design.

For a mid building chimney you may get away with it - ie one on an internal wall - but for external walls, gables and especially freestanding stacks then you need to retain structural integrity lower in the building to counter the turning moment of the exposed brickwork. In this instance you could insert steel lower such as in the first floor subject to calcs/survey and free up the ground floor space but it’s a lot of hassle to retain something just for looks

Remove the lot - if you take out below you’ll lose all structural integrity.

Use it all the time - dries hard really quickly and easy to sand too. Don’t tend to spray woodwork and use Dulux Satinwood on all woodwork - not sure if you can spray that tbh.

Define “empty”, as it has to have not been used as a domestic dwelling, or had CT paid on it, and not part of another domestic curtilage for 10 years to be exempt. You may also require a sworn statement from previous owners. The “empty house conversion” clause in VAT reclaims is one of the hardest to convince HMRC to accept - I have tried (and failed..!) and that was for a garage conversion that never had a car in it for 12 years and was used as storage for a business.

Yep - hex nipple / socket same difference just nothing to grab on that with a spanner but will work fine. If you can’t get a 3/4 male drain cock then get a 1/2 one and just get a 3/3 to 1/2 reducer

This stuff https://www.toolstation.com/everbuild-multi-purpose-wood-filler-250ml/p15238

3/4 female hex nipple then just screw a 3/4 male type A drain cock into it

TinkerCAD is easy to use and exports directly for 3D printing

Any of the micro inverters do that ..? Makes it even easier as the connection is then just into a rotary isolator.

Rads all the way - unless this is part of a much bigger plan, and you’re installing buffers etc then just go with conventional heating here.

Flush mounted ..? https://www.blauberg.co.uk/en/ceiling-mounted-vent-grille-adjustable-ventilation-diffuser-extract-air-white

Background run rate on these is about 45Wh so if you said 100Wh in total, then both units running for a week is shy of £6… Will you be turning the fridge / freezer / TVs off standby when you leave the house as those are probably using equal if not more …? And the whole point of background ventilation is that it runs permanently !!

Cold bridging at the sole plate and detailing there for condensation is the biggest problem. Some use a sheath of PIR over that point but not seen a good solution yet unless anyone else has.

So by the time you’ve finished it’s £4K, plus internal filters and other bits. That’s about 20 years payback assuming you don’t have to replace any parts. £4K gets you pretty much a full 4kWp solar system that pays back in 5 years at todays electricity rates. I have a pair of buried IBCs, total system cost of about £150 with the jet pump and that’s for garden only.

PSV is Irish equivalent of MOT Vivaro’s don’t age well without religious servicing and had a nasty corrosion issue on the heads. I’d take the higher mileage Nissan any day

First rep is talking crap - unless he knows every floor type you’re planning then “just running hotter” isn’t an option ! You cannot dump 65°C water into UFH and hope it works ..! SM - or retrofit UFH - only works when you have lots of insulation and can lose the 25mm of build up in door frames etc, and it’s really a bit of a fudge of a solution. I would stick with rads and oversize them for the requirement based on the heat loss of the rooms, size them at D30°C rather than D50°C so if you decided to go with a heat pump in the future they wouldn’t need swapping. If you’re hacking the system about then consider repiping the whole house but as a minimum get the old system properly power flushed and consider adding new radiators throughout.

Quickest is just to remove the overlap and do DHW at say 05:00 and then again late afternoon so you’re missing the heating periods.

Or just wire it as a standard W-Plan with a diverter valve (not a mid position) and use the satisfied connection on the tank to trip back across to heating. No need for relays as this is all standard stuff. Used to be used a lot but not as popular now since multi zone S Plan has been used.

Yeh that’s designed properly !!! OP is in for some serious re-piping and rewires to drop this to what you suggest. Poor man’s W-plan is to not overlap the programme timings and tbh there are 3 manifold pumps here vs. one system pump and it’s going to be an uphill battle anyway !!

The manifold pumps are overpowering the DHW / Supply circulator - what are they all set on .?? Sounds like you need to up the speed on the main circulator or do some timing changes.

No programme overlaps on the system ..?? So DHW is off when heating is on ..?

S Plan or Y Plan setup .? Most likely the 3 pumps are back syphoning through the coil in the cylinder due to a valve letting by. Non return valve (flap type) would stop it in the flow to the cylinder.