JohnMo

It will vary a little as system pressure drop increases.

To get that, a LLH header or additional pumps will not change anything. The boiler ramp rate (degrees per min) will be just the same, it's hard programmed into the boiler controller. The only way to get your boilers to work exactly the same, is to install exactly the same boilers, or simply delete one (old conversation).

As mentioned above a slow ramp is good, it's energy efficient. Fast ramp in flow temp requires a lot of energy. The way to operate a boiler is exactly the opposite to what you want to achieve. Reduce flow temperature let everything run longer, minimise boiler wear on boiler and longer steady state running. The house will benefit from a more stable temperature. Our Atag you can adjust how quickly it accelerated to max temperature, even doing DHW I had it dialed right back. It would take 20 minutes to get to 60 degrees, by that time the cylinder was at 52 degs and the boiler returned to heating the house. Slow accelerate spends the max time in high efficiency maximum condensation mode. Fast acceleration spends the least time. Think you are now in the making issues for yourself mode. Yes make a cup of coffee or tea and read the paper, or take the dog for a walk. Stop making issues out of normal behaviour. LLH - no Additional pumps - no Get on with life - yes.

Me also, zero issues, a good price at the time.

Remember reading something a while ago, lots of rules and limited components approved. £18 sounds like a non approved thing Just found the thing I read https://www.ofcom.org.uk/phones-and-broadband/coverage-and-speeds/using-a-repeater-to-improve-indoor-mobile-phone-signal

Top image will not work as you need an inspection chamber at each junction. 2nd image you are going to be metres below surface by the time everything meets up with the fall requirements. Don't like the angles, would aim for 90 degs Where is the treatment plant going? Start from there first. Longs runs equal very deep.

If he ignores this, then there is no hope.

So do you have suitable air gaps either side of the super foil? You need these sizes of battens either side to get the performance advertised. If you haven't bought or started doing insulation yet, I would use Mineral wool between studs (Rockwool Flexi or Frametherm 32) then full sheets of PIR on top of studs and a small service void batten.

That bloke down the pub, now I understand. At least it's all straight now.

Or just switch off the ASHP and do nothing. He seems to want a cold house. This threads being going on for 2.5 years and nothing changes. He had a cold house then, and still does.

Nothing particularly wrong with multifoil, but it needs to be used correctly and have the correct airspace either side of it, which is often not built-in. I wouldn't use in isolation, but with other insulation. But when you take into account the correct air spaces either side, it doesn't save any space, compared to mineral wool

Is that your main insulation?

If I only paid £70 for all electric I would be well pleased, but living in a cold house and have an angry wife. Not having heating on, causes house temp to be cold, everything becomes damp - funny old thing, all the things @zoothorn describes. Suspect the heat pump could heat the building well, but is never given the chance - £70 bills leave no place to hide, when you have a 9kW heat pump. The heat pump is off more than it's on. I'm running a 4kW heat pump, only pay 15p per kWh and my bills are way more than that.

Heat pumps are fickle things. During the commissioning of our heat pump, I tried various ways of operating, a high fixed flow temp and thermostat and Weather Compensation. Surprising both got a similar CoP, BUT, and it's a big but, the weather compensation had to deliver way less heat energy and used way less energy for the same house temperature. Both tested on very similar outside temp performed over 24 hours. Weather compensation delivered 48kWh and the fixed temperature had to deliver 81kWh. Which is bonkers amounts of heat being delivered. Sounds the perfect place and house to live in! Living with a crap heating system (or mainly rubbish setup and or operating manner I would suspect) that cannot warm your house, all so you could get a free cylinder, you could have bought yourself for £500. Doesn't really matter what house you live in, a steady flow of heat into the place it will get warm, even a stone house. As soon as you switch off the heat source that energy starts to be lost and the rest of the energy trapped within the structure also goes. Leave it long enough the effort to replace the energy becomes an uphill struggle - I suspect your heating system is operating like this. Digging out floor if it's to add UFH then you will adding a further delay in getting heat into the house. If you have a thermostat in the warmest part of the house, you system will go on and off and the cold parts never get warm.

One of the main reasons passivhaus specify 3G is based on comfort. The window internal temperature of 3G being very close to room temperature, so isn't uncomfortable to sit next too. The lower the performance the more uncomfortable they are to be near for long periods with it cold outside. We have a bay window, with floor to ceiling glazed and I sit there quite a lot, it's comfortable whatever the weather is doing outside. Not sure I could do that with 2G.

Sorry I was talking Uw, so frame and glazing (Ug and Uf).

You need a really good frame, or a good one and Krypton gas filled.

Or don't do a cavity at all, and do externally or internally insulated.

I've done both, woodcrete ICF is a good hydrophilic material I believe, but good airtightness and MVHR to capture any ventilation heat losses.

I waited until I had a skip full of stuff, off cuts of insulation, plasterboard and general building stuff.

Does your house leak air quite badly? Old houses don't need additional ventilation if the have the fire places still there, they move air at a high rate. Gets back to the point made by @SimonD that airtight houses have better control of passive stack ventilation than a leaky house, where flows can be very high

Can you get it to do a taper charge, so backs off the 10% or so of the charge period

Then ask it the same question tomorrow, and you may get the polar opposite answer

Building control, via a completion certificate. While building and site is under planning permission and the agreed scope of works, permitted development isn't lawful. Substantially complete as mentioned @SBMS, no idea where that comes from. Extending that, you add an extension to a new house before it's complete, sure that's not allowed!

Zero benefit having a battery except for PV offsetting. I'm on Cosy and battery gets charged 3x a day so all my electricity is cheap rate 24/7. I would just get a decent tariff that pays export and allows cheap rates. Move supplier if you need too