JohnMo

Get it serviced once a year. First couple of years we needed to replace the 10 and 5 micron every 3 months, it's now done once a year. Had water analysis done in the first couple of years, now don't bother. Why bother with pressure analysis, you get that every time you open the tap? Your fine filters are in clear filter housings are they white or mucky? Your pressure will change on a continuous basis as the accumulator pressure switch is activated based on a hysterisis. Generally don't overthink it.

And an Essex flange

Would be good, but one chance to get it correct, then hello new cylinder

All depends on location and wind loading, size of glass panel and height of drop. Really need structural engineer to specify design requirements and go from there. Article here to read https://www.iqglassuk.com/technical-advice/regulations-and-best-practice-for-glass-balustrades/s88644/

Here are some proper layouts and flow diagrams - they feed into the secondary return port not the DHW out port. http://heatweb.com/literature/Amazon_HXIN.pdf

If you are pulling from the bottom and injecting higher up, you will be pumping up hill. Depending on pipe runs there may be a thermosyphon formed as hot water cools, this will travel downhill, so you will need check valve downstream of pump.

Discussion on plate loaded cylinder here https://community.openenergymonitor.org/t/anyone-else-with-a-monitored-heat-pump-and-a-mixergy-cylinder/23825/69?page=2 It shows a mixergy cylinder layout, it draws cold water from bottom of cylinder and deposits hot back at bottom of cylinder also. So I assume the hot water at top cylinder isn't disturbed.

Look on eBay, they can be way cheaper.

An expansion vessel only has one pipe connection. Generally a volumiser will have only 2 connections and will be only on the return or flow piping. A buffer could be 2, 3 or 4 connections, but will have flow and return piping connected to it.

A Y type looks like this A ball valve strainer looks like this This what removed and replaced with

Nothing like out of context quotes, to make a point - that discussion was about room compensation and UFH, you said it was needed and I stated I tried it and it didn't work - so not relevant to this discussion. In that case, boiler at min flow temp kicked out over 9kW, I only need around 3kW at max demand, so no surprise it didn't work.

Unless it's an Atag (and others) then it runs just like a heat pump, like it or not. Up to about 40, has a dT 4 or 5, dT progressively widens but not be much. Doing DHW with ASHP cylinder and flow temp cap of 60 degs, would slowly ramp up flow temp over about 15 to 20 mins, exactly the same as heat pump and settle at a 4 to 5 Deg dT. At the end of the cycle dT would start to drop when it hit 60 degs, going down to about 3. Both were done with zero cycling. Built for the UK market, and simple S and Y plan you have 20dT and that's about it. Modern boiler built really for Europe (Atag Viessmann etc), W and X plan and weather compensation, you get a boiler that runs just like a heat pump.

Think I would install before the external walls so you can get a crane in with ease. Concrete floors, concrete stairs, will it start to look like a carpark or industrial building?

It grey here also, but I am currently importing 5.7kW of free electric - thanks Octopus, charging battery and doing DHW next. Currently at 240V, 1 hour ago 247V, but does swing up to 250-251V, especially if exporting.

Got a bill today - mid July to today.

No idea what you are trying to ask? You seem to ask one thing then if you get answer you don't want you go on a tangent. You only do tight transit through room if you are running multiple zones, otherwise you would use the pipes spaced where possible to utilise the heat before getting to the end destination. Make the pipe work for its cost. Only room I have transition pipes in the utility, because manifold is there. Hallway, main bathroom are all heated by using pipes going somewhere else, suitably spaced to match heat required. Original ask was can I do 50mm spacing because you cannot achieve heat output any other way. Now you are talking transition through rooms? If you answer the simple questions asked, you may get some sensible answers, until then I will watch but not answer anything further.

I did a white external meter box on a post. Positioned it exactly where it would end up in the house. As wall was built it was moved about slightly. Once water tight box was cut away from meter and positioned correctly. If you need power to caravan, run armoured cable between meter and caravan.

Could of told you a couple of weeks ago, but deleted loads of stuff off the phone, and the Mitsubishi tech manual was one of them.

Suspect a cold day would be about 50% higher than the average. So if your 200m² (add your own area) that's about 50kWh to cover all consumption on the coldest day on cheap rate - let's assume Cosy tariff for now. 50kWh a day is around 2kWh per hour. Cosy gives 8 hrs of cheap rate, so that's 16kWh (2x8) and needs battery for 34kWh. 34kWh/3 needs just over 11kWh battery to cover all electrical demand on cheap rate on the coldest day, if charged three times. The shortest cheap tariff period is 2 hrs, so you would need a 6kW inverter to comfortably to charge. Just add your building size.

If your 3 port valve has secondary contacts that close on valve moving to DHW position, use them to provide pump on off signal to pump. If it doesn't have secondary contacts, piggy back the power from the 3 port valve.

The first video, had two distinct zones, UFH and radiators, which is different from you are doing. The primary circuit was at the boiler with secondary circuits for radiators and UFH each requires it's own pump. You will be running both areas (UFH and rads) on unison, so you really don't need hydration seperation to keep boiler happy. Whether you need dT20 to keep boiler on side with a max flow temperature of 50 is debatable, and something that can be set anyway. Trouble with dT20 thing, is when you are running WC and it's mild your flow temp could be 30 for the radiators, so dT 4 or 5 works, dT20 definitely doesn't as return temp is lower than room temperature. Discussion here on dT settings

So is the left manifold feeding the radiators? The right the UFH? The tee being your mixing valve?

Flow rate goes down with multiple showers on at same time, but you are only delivering what the water main will flow at a max anyway. Two showers is fine, 3 usable but unlikely 3 people would shower at same time. Never noticed any noise ever.

Do you need the tee and join between flow and return between the two manifolds? You will need two circuits, but they are going to stay on all the time. You will need two different WC curves one for the radiators and one for UFH. If you applied the same curve to both circuits it wouldn't work. Mainly because the design day flow temps are different by a big margin.

For £2k you buy a heat pump! But, do what the regs say. They do not mean the same. Double skin is just a additional external layer to the tank, more for protection from impact. A bund is an oil tight area below the tank, which should the tank leak would catch the contents and not allow it to leak to the environment. A bund done correctly allows water (rain) to drain away, but not oil.