Nickfromwales

Your chaps are spot on here, and it’s great to hear them saying this to you as they obviously know theirs stuff. 👌👍

Indeed, as if it’s not “worth” capturing with a costly battery / other diversion then 8 agree it’s just simpler to let some leak away. In the grand scheme it’s an acceptable loss but agreed to be the ‘final destination’ for anything generated.

Yup, you’ll need a bigger buffer, agreed, but £3k now is bucketloads cheaper than all the faff and retrofitting of another device later on / more complex controls / integration etc etc. Physical size will be smaller and neater than an oil boiler being retrospectively plonked alongside the ASHP . You won’t really get a smaller oil boiler either way, so if you want oil then discussing size is moot ( and needs to be based on a min of 15/16kW for this exercise.

OK. I'll retract 'hog', and give serious consideration to 'wash' being downgraded also. DISCLAIMER: I automatically assumed that nobody would want to install a domestic microgeneration system, designed to provide the grid with cheap power, at their own significant cost.

Is everyone here remembering that they DO NOT NEED 3ph to have a wedge of solar and batteries?

Hog wash. Hybrid inverter; then a field full of panels + lorry-load of batteries enjoy zero DNO nonsense.

I can't spell it lol. Fill yer boots

To not install a softener is madness, sorry. Knowing that all the crud and scale is growing on / in everything, from the day you switch on, and doing nothing proactively to defend against / prevent this from happening makes absolutely no sense to me whatsoever. Showering in glorious soft water is fantastic, vs the hotels I stay in ( when behind enemy lines ) where I need to use 3 times more shampoo / gel etc is something I couldn't cope with or get used to, let alone justify choosing NOT to mitigate against! "Go soft or go home, lol". Probably a good time to remind the masses that manufacturers of certain equipment / appliances / outlets will stipulate that; beyond a certain PPM of hardness their warranty goes south and the installer / owner should mitigate, howsoever, to prevent damage / early failure of said equipment. Just "no". Sorry!

If you go for a solid fuel appliance, then you have to allow for terminal failure scenarios, like the WBS being over loaded and the heat demand being zero, so the WBS eventually boils the water and steam becomes the killer. Unless you plan for a sealed and pressurised WBS with a cold mains fed quench coil, forget the setup that you show in your picture. 100% no go. Fit an oil hybrid ASHP from the get-go. LINK Simples.

Indeed. But surely this is down to the laws of physics; as juice out vs juice in is an electrical ballet between the flow of said juice through the 3 coils that perform the metering registering positively or negatively dependant on the sum of the activity of each coil at any given moment? Ergo, net metering is happening regardless of request / intention as it’s a physical occurrence. It would be down to the hardware, yes, and the software registering flow in both directions ( and reflecting that in the reading of the meter display ).

All depends on what the heat sources are. Typically low grade heat gets injected much lower down the cylinder and vice versa. Heat sources are?

To go 90% of the way installing manifolds + radial pipes, and then discount 2 pipes and add extra satellite manifolds seems crazy to me tbh, and I’ll argue is more costly, more complex / impactful, and less efficient use of time / funds. You have to purchase, mount ( and have access to ) the satellite manifold(s) and each manifold then has to have pipes from that to the individual outlets anyways! Drilling 2 or 4 or 6 more holes through a breeze block would take about 30 mins ( and that’s if you had a cup of tea in the other hand which you didn’t want to spill ). But I would be doing what @TerryE says and knock out a letterbox sized hole, load it with short lengths of pvc pipe, and pull the Hep2o through those ( so they don’t get scratched badly by rough surfaces whilst being pulled for the long distances. The major benefits of radial are a) zero joints between appliance and plant, and b) uniform flow rates. If you take 1x cold line to a satellite manifold then that would have to be 22mm pipe and a 3/4” manifold to achieve the same results / dynamic flow rates. More difficult / costly etc than 2 more 15mm or 10mm pipe runs. 👎

If it's a low temp dwelling, then the cheap manifolds usually only feature a regular TMV with a lowest setting of 30oC, which choke to death at that setting. I'd allow £500 for the Ivar pump / blending valve + Komfort manifold. So above + £300 basically. Still a lot of DIY bang for the buck!! @JohnMo could you post a link to that ASHP please? Just interested to read up about it as it sounds VERY cheap.

Ok, so you can choose which meter gets installed?

OK, that MAY work without the additional pump, but you'd have to accept a trial & error install and the plumber having to chop the pump in, in the event of it not performing as we'd hope. Up to you to accept that, as it flies in the face of your plumber.

So who answers this question definitively? Who do I ask for a smart meter to be fitted that supports net metering, and to then evidence it?

As long as the cyl stat and immersion are facing front, you’d be ok to bury the UVC in that ‘deep’ afaic, plus it looks like you have planned spacings to allow its retrospective extraction ( should ever become necessary ). Just make sure the cylinder does NOT use a sacrificial anode. For the UFH, how are you going to manage the differing temp requirements at each of the manifolds? A pumped brach Will only allow manipulation for the flow temp at source, and is not a good idea IMO, especially if one is on an upper floor?

If that's 5m horizontally then you''l likely only need to pump the rads, but tbh I'd prob leave the pump where it is and run with the design you've been given. If you're really concerned about running that extra pump then delete it and just cap end the run to the rads circuit and manage without it until / if you decide to install the rads.

The pump is there to put flow onto each of the heating circuits. You cannot move it to after the T as you'll then be sucking water backwards out of the UFH circuit. What you can do is T the 2 pipes coming out of the LLH and install swing-check non return valves on them. Then the one to the UFH manifold pump can be left 'pump free' and the pump can simply be installed on the leg feeding the rads. If the rads aren't getting fitted now, don't fit the pump. How close to the LLH is the UFH manifold + pump & TMV?

He's good to go after half a shandy.

In a nutshell. Very relevant actually, unless you'll assume they're blind / inept at the good ol' HMR of C They would use their "additive mathematics" to tell you to stop taking the Micheal. A Ring chime is £30. Try fitting that instead?

Is this new works, and subject to BRegs?

Lol. Twat is a bit harsh, you penis. The other favourite is closing the isolation valves to do the work, and forgetting to reopen them. My least favourite was my neighbour asking if I could see why their combi had suddenly stopped working. Flame failure. Went out to check the flue, and the painter doing the outside had bagged the bloody flue and gone home for the day. Now HE was a real twat.

Ok. I'm slowly coming back around to room by room ventilation ( via MVHR or other ). Detailing internal junctions ( if IWI ), eg where internal corners meet, where ceilings meet walls etc etc will be of absolute and critical importance here, or you'll get very localised issues where ( for eg ) dot and dab has bridged the covered cold wall to the interior of the room. This is something I have suffered myself, where I let dab squeeze between the insulation of the two abutting insulated plasterboards in my bathroom. You can literally draw with a pencil where I have done this as the damper part of the wall reacts after every shower is taken. A sloppy installer will just bring the problems further forwards, so you need to vet the installer and be firm with what you expect from them, what the issue is that you're resolving, and how you wish to understand how it is to be carried out.

Same weapon of choice here. I'm blown away by how quiet they are for the money. Easily as quiet as the Stiebel Eltron units ( which command a LOT more of your hard earned ). Can't you provide them with a written waiver, stating that you will meet any subsequent removal costs etc if it all goes south? Once it's in, show the installers how quiet it is and they'll get a very much needed education.