JohnMo

Not sure how useful that is in the real world. I currently have my compressor restart hysterisis set at 4 degs, any lower than that you don't get a successful restart because floor slab has then equalised in temperature and the heat pump has no where to dump the heat. So at a flow temp of 20, in real world you need what ever you are heating to to drop temperature down to 16 - that just will not happen. My WC curve calculation says I need to flow 22 degs at 10 OAT, but I think realistically I may need to set a higher temperature. It's programmed like that for now, if we get a mild day any time soon I can test it. I always find ensuites difficult to heat. We have the bedrooms cool, so heat from the ensuite just bleeds onto the bedroom. But even at around 20 they are comfortable as floor is radiating heat at you anyway

Didn't say it couldn't control well with silence - it can, but you still have flow temperature distortion. That's ok in a mixed system with a reasonable flow temp difference but not in one with only a couple of degrees. Electronic offer zero distortion if you want it, so radiator demand goes, electric mixer become an open piece of pipe.

I posted the information you need, last night so you missed it. I used one, it's same in many respects to most mechanical UFH mixers it requires a minimum (always on) mixing, so there is always temperature distortion through the mixer. You try to regulate this with various internal adjustments but it's always there. You're sounding like me.

Low flow temperature makes little or no difference, what layout you do, as dT for loops is so low. It's currently 2 degs outside and on 300mm centres our flow dT is closed to 2.5 degs. Our pipes are 100mm down, so by the time the heat has migrated to the surface, there is very even surface temperature. I have just up and down pipes, nothing fancy.

We all want that - in our dreams, you can 1 or 2 of your choices - never all 3. Unless you move to another country (not inside the UK)

UFH design get a a free trial version of loopcad, do your own design. Design by room heat loss and balance system out of the box by loop design. Keep everything simple. If you only want heating downstairs you need to design heat output to meet whole house heat loss. Some are ok with that, some hate it. If you have a big hall upstairs stick a big radiator or two and run at UFH temps, if room are a little cool you just open the doors and let some heat in. If you like warm bedrooms you may need heat in every room. But everything needs to sized correctly. Smart homes crap and heat pump is a utter waste of money and effort. Not needed will not help anything. Sorry to be blunt and to the point. Either run WC or a simple centrally located thermostat to drive heat pump on and off (if you do this you also need to run a hotter flow temp so get slightly worse CoP/running costs). Pre plumbed cylinder is an utter waste of money - as 90% of the equipment on a pre plumbed cylinder isn't really needed.

I have two Titon units, without preheat, they just slow the incoming air fan, if it detected a freeze condition is likely and then once cleared back to normal speed. We have seen -9, we are only 6 miles from the coast and have a lake in front of the house, so the worst conditions for freeze up. No issues after 5 years. Would recommend looking at Titon HRV, British made with direct phone support, should you need it, spares are readily available if you need them. Can be as simple or complex as you want.

Just use immersion, I wasn't for it a couple of years ago, but tried it a few months ago (after plenty of here say they heat water that way) and overall my electric consumption hasn't jumped up much. Heavy water use day I use more electricity, low use days, I use less. Latest crop of R290 ASHPs, more or less all seem to do it.

Something like an ESBE VRG valve and ARA600 actuator. Not an on off actuator. Your flow temp difference between GF and FF is only going to b e a few degrees. Lets say 5 degs. GF wanting say 25 and FF 30 degs. ASHP pushes out 30 degs, the electronic mixer just mixes down to 25 degs for GF. This flow temp changes based on outdoor temperature. No robot needed, no 1-10V signal needed.

Almost all currently available heat pumps do this out the box - you only need one mixer for the lowest flow temp zone. Shouldn't need a volumiser either, unless you over sized the heat pump. Basically work on the basis of 20L per kW minimum output, system volume, if you achieve this no volumiser is needed. Complexity - a temp probe down stream of mixer, connected to heat pump control/wiring centre. 3 wires to mixer from same control/wiring centre. Set controller to two zones, set the two WC curves, job done.

Or let the ASHP controller do the work, two zones, so two WC curves, controller can use an electronic mixer, such a an ESBE, the ASHP controls flow temp to coolest flow temp, no buffer needed, no temperature distortion, no additional pumps. Just run as fully open system with two flow temps, one unmixed and one mixed.

Here are couple of documents to get you started UFH-System-Design.pdf UFH output calculation.pdf

Simple answer you ASHP company should do this for you. They need to do a room by heat loss calculation anyway. They will know the UFH design, because you will pass it over to them. They will then be able to state at design temp the flow temp. Flow temp required will also vary with a screed depth and floor make up insulation etc and floor covering. So a little fine tuning may be needed.

Deep sand, doesn't give very good grass, as the nutrients and water just bleed away very quickly.

Top soil by the lorry load is around £35 tonne, if you are doing garden just do top soil. Any other purposes recycled concrete etc. or similar to bulk fill then hardcore all compacted.

Dodgy temperature reading to me, or you have the wrong identity assigned to each gauge? So rubbish in, rubbish out. You seem to making an issue from reading from a £1 gauge.

The other way to it, is borrow ideas for the Adia system and simplify. Have heat pump on its own loop, CCT and additional pump for secondary loop, flow rate and match flow rate with secondary pump. Choose pump with enough head to go through existing pipes as required. Use flow setters on the existing rads at a dT to suit room and flow temps. Heat pump will modulate as needed to meet the heat extracted from the primary loop. Primary pump pulling almost zero Watts as no real head is needed. Whether you actually need to include the CCT is questionable, you just install an additional pump on the piping to produce the additional head required on fixed duty (then there is no fight with 2x modulating pumps), to push though the existing pipes. Then do what you normally do to the system.

And domestic cats kill way more - every year. But no-one complains about that. Don't here any slogans "stop the wind farm and neuter/ban all cats"

Are you not just arguing for the sake if it? No one one says (well maybe a few some ill informed are) that we must stick with hydrocarbon energy sources. NIMBY's are complaining about anything and everything, even if happens 20 miles from them. If we can get all our energy from renewables (which doesn't include nuclear) let's fill our boots. Distribution of said electric needs to happen, more NIMBY action there. In the time to bring renewables on line oil/gas needs to back fill. All very simple.

Panasonic, Daikin, I'm using a Myson iVector. You need one with adjustable water flow temp fan start permission. Some only really designed for gas boiler so have a fan start permission of say 45 degs - which is no good. These fit in the none adjustable fan permission category, in most and are designed to allow cooling.

Think it's there to cover all bases. Use the installed pump of the ASHP to overcome heat exchanger and piping to house. The secondary pump is there to push though micro bore if you need to. It's a one box to cover a lot of situations. Still not seen anything on how it works with UFH. It says one flow temperature systems including UFH are doable. But not seen any details.

They can't, almost no country can, it's a global market. It's what I mentioned previously, it shouldn't be a binary gate, each fuel, renewable or hydrocarbon has a part to play. Trouble is the environmental activists, demonstrate, with their plastic tents, plastic drinks bottles, fleece jackets, nylon ropes, and don't understand all that vanishes with no oil. The point should be what mix of fuel and energy sources leads to best self reliance. A grown up discussion needs to be had, but British politics, the press and the money, will never let that happen. You need people power to revolt and standup, but most couldn't give a stuff or cannot or not interested enough to understand the issues or possibly solutions. In the round renewables is the way forward, but for a long time hydrocarbons will have a big part to play, especially in England, Scotland way less so.

It's sold on the basis that no radiator or piping changes are needed. After a few weeks of capturing data, the home owners gets the options - stay as you are, and possibly upgrade radiators, for a given cost v cost saving on running cost. Suppose the idea is for £4k plus a day or two labour you get a heat pump. If you have a cylinder already they can use that as well.

I installed two units in our house, self installed, well under £2k all in. Ebay can be your friend - if you accept warranty is unlikely. But in the UK you don't need pre heat or enthalpy heat exchangers, you don't need CO2 sensors and really once setup, and running, you don't even need boost very often - we last had boost on (manually) over a year ago, auto boost just isn't activated. Manual boost outside bathrooms and in kitchen, or manual boost in kitchen and humidity activated elsewhere.

I've seen that way of doing things mentioned several times and the real world a lot of building could get away without much in the way of radiator changes. VAT, include a contingency (deposit) to return assess and make x pre priced changes - fully refundable, less second visit service charge? Explain you could remove that charge, but full VAT, plus any grant funding, that was too have been included, would be payable for the second visit.