JohnMo

You need to take a step back. Mitsubishi and Vaillant looks like it maybe 6kW flow rates, the other numbers are nonsense. The numbers you are looking are the extreme the pump can flow not the target flow rate. The important number is the target flow rate and max pressure rise to achieve that flow. You need to look at the pump curve and where you need to be on it. For those flow rates in most likelihood you will need 28mm. I am flowing around 1m3/h (16.6l/min), the path mine takes is quite convoluted about 12m each way in 28mm in Hep2O and the longest pipe in the UFH is around 110m (16mm pipe), all flowing from the ASHP circulation pump. Plus the same pump also pumps to a single fan coil in 15mm Hep2O another 15m each way in another direction. I would choose something you can get parts for locally, Hep2O is readily available on Sunday morning if you need a bit. Find your target flow rate and the max pressure drop first. Calculate the pressure drop on the proposed run second, size pipe to be under pressure drop max figure. If you piping goes up 4m and 2 that's a 2m head ride when you calculate. Put a bleed at high points, makes life simple when filling and getting of air. A tee will add little or no resistance, Hep2O is good for this also as the pipe inserts are thin wall steel. Or you can do these sections in copper and use straight connector between Hep2O and copper.

I have one at the top of my cylinder (top upwards exit) goes up about 50mm and across cylinder and then down. The downwards pipe is stone cold the top pipe hot.

I never bothered asking, wasn't really aware I had to. But started paying council tax that day. No one seemed to care, so didn't ask questions.

I did a write up on installing a hybrid heating system, not if you saw it? The system is installed so it can have the boiler taken away without any effect on the heat pump system. A low cost version if you don't have a plate heat exchanger kicking about, is a simple close couple tee instead of PHE. If you needed to buy a boiler, as small as you could find would do the job.

It does make it all a nonsense, possibly refilled all holes after leak test, then will the first to complain they have mould everywhere.

Trouble with Scotland MVHR is mandatory for an airtightness of 3 or below. If you hit 2.9 you have to install MVHR before BC sign off. But have to say MEV or dMEV can be made to be incredibly efficient with self modulating trickle vents and dMEV or MEV altering flow rates based on demand. Very low running costs, no filters, no heat recovery but on an otherwise well insulated house running costs are going to low anyway from a heating perspective.

Probably is, maybe one of the reasons a lot of States in the US mandate heat trap, orientation pipe work. i.e. limited length upwards, horizontal and then drop down vertically on all cylinder pipe connections, as soon as practical, to stop thermal gradients moving along piping, leaching the heat away.

But you wouldn't do that in real life. A heat pump cylinder generally has a thermostat within a foot of the bottom of the cylinder. So reheat times are generally manageable in a normal house without the house cooling down to much. Then the reheat volume and time is purely based on thermostat hysterisis and cylinder shape and volume from where the thermocline sits (not total capacity), which could be quite low as it may well be in @Dave Jones case my 6kW reheat times the last couple of days have been around 30 minutes, but the water has to travel about 20m each way so I do loose some efficiency.

Plus 1, that's £11k m2 and you still need second fix and paint. Did you miss the bit about gold leaf external finish?

I based it my reheat time from call for heat to stopping heating and allowed for the extra volume of the OP.

Mine is wood any size you like

Did think that also, but the 16m2 area and 100m of pipe is only around 12L, which isn't enough.

The local company that made our windows also made our doors. A sandwich construction, with a PIR insulation core, total door U value is 1.0 and airtight. Any issues they are 5 mins away. Go local

5kW is perfectly adequate to heat any volume of water. It just a matter of how long it takes. Would suspect the reheat times will be around an hour, from a fully depleted cylinder. UFH just use 16mm, output of 16mm and pressure drop on 12mm isn't helpful. Or dump the idea of UFH. To make your heating work the way you describe during the heating season your UFH will need to be close to the room temps you need all the time as it will only be putting out around 0.5kW. that will never reheat the place if it goes cold. As @Dave Jones says fan coil, that's what we use after dumping the UFH in our garden room. You will need a volumiser (about 40 to 50L) to stop the heat pump short cycling with only one or two fan coils as system volume will be too small without.

? Photo of washing machine?

Could you just staple small hole chicken wire under you floor frame?

Backwash may not be required if you are already filtering debris (turbidity) upstream. The backwash is only there to get rid of debris if used for filtering also.

Don't you need something like this? https://silverlineuk.co.uk/product-category/well-water-treatment-borehole-water-filter-systems/ph-correction-units/

Do you have the full background to why it failed, things like after hammer, can easily exert enough energy to break things. Pipe stain can do similar. Age etc - Without the details all a bit meaningless.

I am really doing it because I have a nearly new boiler sitting there. Will get pennies to pound if I sell the boiler. Did it as an experiment. But also to show it's easy enough and provided all the information for someone to replicate, especially with a radiator system as a retro fit. Around 80% reduction in CO2 emissions compared to a boiler alone. Re utilisation of a combi boiler as a system boiler or keep the combi part in service if you don't have the space for cylinder. Think the statics are the average house requires 6kW to heat and 80% are below 8kW, but the average size of boiler sold is 30kW. So you only need the smallest heat pump to make a real difference to CO2 output. At 7 degs the house heat demand is also half of the -3 heat demand. So most houses only need 3kW. But have the average sized boiler of 30kW, which doesn't turn down enough, not to short cycle when it above zero.

Layout and control schematic Heating Layout and Control.pdf

Sorry no. A long time ago I did a post on here what it me, but never compared to any other build method. But two of us neither done it before, took about 4 weeks to build our walls. 70m perimeter and and average of 3m tall, with quite a few changes of direction on the front wall, which fiddle and time consuming.

It's not, but many years ago it did.

Greenwood CV2GIP in each room done, silent, smart humidity boost activation, 3 wires is all they need.

Yes No stipulations about that any more.