JohnMo

Are rubbish with UFH as you get big under and over swings in temp. The one I mean mentioned is about £60.

The two statements seem to be a contradiction. Don't need need much heat and astronomical to run a heat pump? Basics are if your house needs 3kW at the design day, you need 24 x 3 is 72kWh. Via a panel heater at 30p per unit is £21 per per day. If you design day is -7 and you need 35 water flow, your CoP will be 2.8, so about £7.80. Most other times both will.becway cheaper. Heat pump are either on all the time at a low rate or batch charging at an elevated temperature but only if yiu use a time of use tariff.

Ok, so you two ways to go with UFH attached to radiator system. Slow and steady via a mechanical or electronic mixer. I would go towards an Ivor mixer, they have plenty of adjustments to get things right. Then run at a slow steady rate. UFH when run long and slow can be self modulating. An electronic mixer can be good and expensive, in most cases not really worth the expense. I am saying that as a person that owns one. Have a low hysterisis (0.1) thermostat (Computherm Q20RF for example) connected to the pump stop and start.

I spoke to them last year, if it wasn't connected to their heat pump they weren't interested and said it only designed for their heat pump.

To add UFH your floor insulation needs to be very good, most retrofit are not. Also control really depends on floor buildup and depth of screed. What's the motivation for UFH?

But wired to priority hot water, not both together assume. Grant have a similar setup as standard, but a note saying the timing has to such that both dhw and heating cannot occur at the same time. My cylinder actually came with diverter valve as standard.

22mm will be fine for that size of heat pump. But regardless I would always go for 3m2 or bigger. The smaller the coil the bigger the CoP hit doing hot water. My 210l 3m2 slimline cylinder takes about 40min to reheat to 50 between thermostat hysterisis set points. 6kW ASHP max flow temp is 56.

I don't believe armoured cable needs to be trenched anymore, so could run a ove ground

Here is an image from the Chofu manual Chofu-Operating-Installation-Manual.pdfby

At various points in my career (at some points prior to getting degree), I managed and mentored nearly qualified and also Chartered or nearly Chartered Engineers, most had no clue how to move high level learning into real life situations. They could speak at great lengths about NPSH (net pressure suction head) for pumps, but would walk straight past a pump on a plant as they had never seen or touched one. They think they are Engineers because they are allowed to be Chartered, but really shouldn't be allowed to be chartered for another decade. There is a lot to be said about starting at the bottom and moving up the ladder, with suitable learning on the way.

There really is nothing to the design of a heat pump plumbing. Single zone (if you want zones you need a buffer). You need around 40 to 50L of water engaged at all times. Let's say a 6 kW heat pump. Flexible hose attached to heat pump, then 28mm pipe to a 3 way diverter valve (not a mid point). Normally open port to heating system, normally closed to cylinder heating coil. If UFH either direct to manifold (from diverter) or via a mixer and pump (general it needed. Common return pipe. Heat pump cylinder (3m2 coil).

The video about the spreadsheet https://youtu.be/kVaxAfXQPDU?si=BXgkkLaUM7II-OOb

It does you need to read the manual. I have attached a spreadsheet that allows to match different mixes of series and parallel solar panels to different immersion heaters to get the correct response from both the PV and immersion. Solar PV Calculator (1).xlsx

Trouble with DC you need to get a balance system, if the impedance (think that's the correct term) isn't the same you get rubbish output. Also to get the best out of PV you could do with mppt. Not cheap but does what you want out the box https://www.windandsun.co.uk/products/my-pv-elwa-dc-immersion-heater

All true, suppose it also depends on qualifications as well, city and guilds levels is a technician only, NVQs, ONC similar. Would expect an Engineer status doesn't really apply until you get to HNC and degree level qualifications in a relevant subject.

I an engineer if I can take a lump of metal and form it to become a useful component part of a machine, whether as repair or new design, or am I an engineer only if I can sit in front of a cad/cam and produce design drawings along with some calculations Both could be an engineer, or neither could an engineer. Depending on your level of learning. An engineer needs to understand things at a fundamental level, know the theory, this comes from training. If can form a useful competent out of metal AND you know why (from your training) you have a certain surface finish and hardness and what the bearing clearance are and why, you maybe an an engineer, if you are just following a set of drawings blindly, you are not an engineer. Same as the person in from of a computer.

I do mean trickle vents vents in windows, but not the normal rubbish 50p version they suppliers normally install. You can get self regulated ones that only as much as required and also have them with incorporated noise attenuation. Or you can ditch the window trickle vents and do through wall vents. dMEV is designed to cross ventilate, so you need to have under cuts on all doors also

Not sure that is true. I don't have one For your heat demands 10kW is way too big. Nothing wrong with the Grant units though. The 10kW unit puts out 11.1kW at 7 degs, you will most likely only need about 1kW. Get the small one 6kW. Find a different plumber

You need dMVHR in every room to be effective, so gets expensive. dMEV cheap as chips, costs buttons to run and buy. Only fans in wet rooms. You really need decent trickle vents that active on humidity or are self regulated.

Do exactly as they say, otherwise you will have a month delay. I sent warrant plans when they asked for planning drawings, got the a rejection letter...

A combined, MCS heat loss spreadsheet and shite in and shite out from contractor. Cylinder temp does not need to be above 50. UFH will be closer to 30 to 35 I suspect. If your max heat requirements are close to 3kW, you really need to look at heat pump turn down as that is a big pump. Biggest issue will be required flow rates for water. 3kW only requires around 10 l/min, you may have to manage 20+?

I have a buffer for one zone, but changing the timing and flow temp a little has allowed me prove it's actually not required, so will be removed next month, along with electronic mixer and pump for UFH. Will reinstate a small WC of 3 degrees, starting at 3 degs OAT and stopping at -3 OAT.

The wall section has plenty of cold bridges to sort out. You insulation should form a continuous unbroken line, you seem to have breaks everywhere. You I beam bolted into the concrete, just straight through the insulation, lots of condensation will occur. The steel by the glazing also looks the same.

https://www.bpdstore.co.uk/glidevale-energy-saver-humidity-sensitive-trickle-ventilator/p/182 Plus the links I added above. Also look in the ventilation section on here, plenty of mentioned ones there also. The other thing to look at is self regulating trickle vents. I paid just £300 with certificate.

Fig 2 has a curve already built in.