sharpener

I gave up trying to think how this might be done using an HP I am not familiar with and not knowing what flow temps the 3 different classes of emitter were designed (?) for. Are there mixers for the UFH for example so the rads can run at a higher temp (not optimal for the UFH)? As well as the schematics it would be good to have the part nos. or pictures of these two smart stats; later though you seem to imply the HP is controlled by only one.

Two basic options. Buy a Chinese hybrid setup from Solxxx where xxx are more or less letters of your choice. You get whatever they are capable of. May not be fully compliant with anti-islanding regs and so forth. Difficult to integrate with existing or extend/expand later. Buy Western-designed separate components e.g. Victron charger/inverter, Fronius grid inverter, 3rd party batteries (probably from China) e.g. Pylontech, BYD. Very flexible. May avoid you having to scrap your existing stuff. I see your existing setup is described in this post. Tell us also what there is scope for in the way of more panels. Also size of house, lifestyle etc inc HP, EV and cooking preferences.

It's not entirely clear to me if this is the original installer or someone you have got in subsequently to advise. If the former he clearly should not be on the HG register if he did not query the architect's original spec and could not subsequently sort it out better. As @JohnMo says wind up all thermostats out of the way and get the basic Weather Comp properly tuned up to begin with. Yes it is bound to cycle on and off at this time of year bc the heat demand will be quite small. Then later you might be able to add specific programming (e.g. extra heat in the GF shower at particular times of day) though that might not work too well depending on what the system time constant is. OTOH if it is many hours then a time-of-use electricity tariff might give you considerable savings.

At least the mine engine houses perched on the cliffs are quite picturesque, unlike the slate quarry remains at Blaenau Ffestiniog. And the Eden Project is an imaginative use for a humungous clay pit. Promising new process for recycling old concrete into new cement here https://www.cam.ac.uk/stories/cement-recycling.

I had a similar problem and bought a new rubber seal kit from Screwfix, possibly this one. It was not a very good fit and was prone to spring out again. Eventually I put a block of wood behind the connection to keep it all pushed in place. Maybe the other kind would be better. The pipe was however long enough to reach past the "ridge", I think you need to fit it like this as it will help centralise the pipe in the hole whatever seal you use. IIRC the hole in the ceramic was centrally on the axis so I didn't have your problem. You could cut radial slots or holes in the end so even if pushed right home there will be room for the water to escape from it sideways.

We couldn't get more than 3.68kW so our 4.4kVA inverter has to be restricted. Is the DNO now allowing you a beefier connection or is it a case of adding the extra power on the battery side like we did so you avoid this? Yes. Dividing the array into two parallel strings will halve the voltage and double the total current.

Yes almost certainly, but (as above) anything over about 4.5kW is probably not worth the extra expense. However there are practical considerations like the shape of your roof and what your chosen installer prefers to fit. I had a quote for 10 x 400W panels, but the day before he was due to install he pulled out (and nearly left me with a bill for a scaffold tower). New ppl couldn't supply the particular long thin panels that fitted best so I had to settle for 8 and a bit of shading in late afternoon. They told me they would bring their own tower but in fact the crew turned up with just a ladder and carried the 25kg panels up that single handed. Which was almost certainly in breach of HaSaW Act, and scary to watch.

Not sure of yr basis for this. Perhaps a legacy from flats having storage heaters, we once owned one, son's flat was also converted from that to gas ch hence some very bizarre wiring. Not sure which way round the thinking is. My 2nd array has 8 x 405W panels with a 48V 60A Victron MPPT bc the 70A was a lot more expensive, was an older design and had less flexibility. But equally if you are limited to a 3.68kW inverter it is better to have more panels than that as you get more output in the shoulders of the day and the seasons, for this 20% is thought to be the sweet spot between capital cost and revenue.

How long is a piece of string? What do you mean by "the inverter"? Few inverters will take 720V though IIRC there is a big new Victron one that does. You also need to be careful the open circuit voltage at minimum expected air temperature does not exceed inverter rating. 18 panels if of the current typical ~400W output will be 7.2 kW. Overpanelling up to 20% is reckoned to be the max sensible amount so that would imply you need a 6kW inverter as a minimum. That would probably have two MPPT inputs so 2 strings rated at 360V 10A, sounds about right.

In the sense that you will require it to register for an export tariff under Smart Export Guarantee which IIRC is what the replacement for the FIT scheme is now called. Intelligent Octopus Go and maybe some of their other tariffs pay 15p/kWh, there was an experimental way you could get this without MCS but you had to pay £250 and produce a structural survey of your roof, don't know if this is still available. See also this thread.

If as you should you have a balanced cold feed to the shower you don't really need a thermostatic mixer, and ordinary one will probably do, that's all I have. IIRC the cartridges for the common MIRA shower controls are interchageable in the housing so you might be able to convert it into a plain mixer by replacing the innards. Failing which I think at least the pipe centres are a common pitch so it might not be too difficult to replace the whole thing.

Can't get that, as smart will not talk to outside world. OP might - or might not, he is in NI.

Assume you mean not switch off completely i.e. leave energised but turn off on its controls so the pump anti-jam cycle can run. Last time I looked it was ~6 years IIRC. Octopus Cosy has two 3-hr cheap periods every 24 hours so you can get two full cycles a day which is twice as good as E7. It also gives us a second bite at charging the Thermal Store. If you are looking for payback then a TS (basically the biggest tank of hot water you have got room for) is better per delivered kWh of space heating than a battery, not least bc of its 20+ yr projected life. Not mentioned yet is adding provision for an EV. That soaks up quite a bit of our surplus generation. Intelligent Octopus Go is in some ways a better deal that Cosy but only cheap at night.

Yes that's right. There are some complex arguments though. If you have an HP then it is theoretically better to use that for HW at all times bc it has a CoP of maybe 3 when producing HW rather than the Eddi/immersion which is by definition 1.00. From the planet's pov this is the best answer. Many ppl program the HP to produce HW in the early afternoon when air temp is higher so HP is slightly more efficient the sun is most likely to be out demand for space heating is less Octopus Cosy e.g. has a cheap window 1300 - 1600 or as I plan to do, in the small hours when I can buy electricity for less than Octopus will pay me for exports during the day. When the sun goes behind a cloud the PV generation may however fall below what the HP needs. If it draws on the battery well and good, you have only the round-trip losses to consider. If it draws from the grid you will have to pay for that (but is still good for the planet bc total demand is still lower). So in these circs the Eddi may reduce your personal bill. Whether this is worthwhile depends on balance of import and export tariff you are on. Also it is a useful backup and in summer you may want to switch the HP off completely to save wear or bc you sit outside near it.

G99 application won't cost much if anything. If you can afford it I would install the biggest system you can bc DNO might take a more conservative view later about adding generation so get your bid in first Other ppl agree the proposed system is probably not big enough for yr needs Yr current installer may go out of business or not want to do it later My experience is that getting other installers to add to a previous system is sthg they don't want to do Battery mfrs continually change their product ranges so being able to add capacity later is not a given It will be cheaper overall bc of economies of scale, and some costs e.g. repeat scaffolding will be avoided My intention in 2011 was to expand later with a 3rd 2kW inverter, but once batteries became affordable that was not a sensible route to go down. If I had my time again I would - DNO permitting - have covered the entire roof with 28 not 16 panels from the start and benefited from 75% more FIT income. This would have more than paid for an 8kVA Victron inverter in place of the 5kVA. This is only just big enough now and will not be able to supply the HP from battery on top of everything else. Fortunately it has 50 amp grid pass-through capability.

Quote seems reasonable for what they are proposing to fit. If you cook by electricity I think you will need a bigger battery and bigger inverter to cope with winter evenings. Depends if your aim is to rely on charge overnight on a ToU tarifff, or can top up as well during the day e.g. on Octopus Cosy (can you get it in NI?). Probably the 7kW PV will be too much for you to use it all in summer, but not enough in winter. HP will drain the battery if you are trying to have it run off that on dull, short winter days. All based on our exp of 6.9kW PV, 5kVA Victron Multiplus II, 10.65 kWh Pylontech over the last 18 months, so quite similar, HP yet to be installed.

Yes. But Honeywell make lots of different controls. I have inherited 4 plain thermostats for the UFH and another on the landing. And have also got their Evohome wireless TRV system for the rads. so assuming there is a grain of truth in what the plumber said I think it must be some kind of smart stat.

OK. I was trying to keep the explanation simple as OP had not heard of R290. Yes I am planning on getting one fitted, that is mainly bc the tall thin form factor is better suited to my site not the refrigerant. As you point out the OP should begin with a heat loss calculation. 55m^2 new build should require only the smallest of HPs though. So I am surprised this would cause any real noise problem at 4.5m. As an example the Vaillant 3 or 5kW emits 54 dBA sound power @ 55C flow, which translates to 32 dBA at 5m distance. These figures probably comply using MCS methodology (they are 6dB lower that my proposed 12kW which would require only a 5 dB partial screen at a very similar distance). But the planners have said what they have said.

No, as it is tidal the water does not even come up to our property boundary for 12 hours in every 24, not at all at neap tides. There is also an aquifer which was discovered when we had the underground rainwater tank installed. Tapping into that would theoretically give a good supply of heat at a steady ground temp say 11C but it is 25m away at the other end of the house from where the HP has to go.

Sounds like it is basically functional but a control issue. You have to know what you are doing to incorporate third party controls. What exactly is the role this "honeywell" control is supposed to be playing in the system, is it some kind of smart room stat? If you can give us a further description, picture and/or exact model number it would help. Others may know what is usual for the Samsung you have got. Absolutely, stick to your guns!

For clarification is this a bungalow? If not how is the upstairs heated? R290 (propane) is the latest refrigerant gas which some HPs use, it is more efficient but inflammable so there are restrictions on putting them near doors and windows. 55m^2 is quite small hence you will not need a twin-fan unit. So it will probably be lower than the window sill, which is OK (since propane is heavier than air) unless it is actually a doorway or there are open drains nearby. Plenty of good HPs about that are still using R32 which is non-flammable so does not have this issue.

1. Presumably a short return fence on the end of the house will screen the HP from the neighbour's window. 2. If it uses R290 check it is not too near the kitchen window 3. Could you run the primary pipework through the kitchen so the heat loss from it is inside the thermal envelope? N.b. I put up an expensive fence from Jacksons thinking it would see me out. But the posts rotted through in less than 10 years. I had a lot of trouble getting them replaced under warranty, it was a lot of extra work to put them in and the fence doesn't look the same. So don't pin a lot of hope on the 25yr warranty on their acoustic panels.

@JamesPa is your man for this. What have yr planners actually put in writing about what they require?

Well for a start there are splits and gaps in several places, if water can penetrate it the insulation properties will be compromised. And although my install hasn't yet been done so I have nothing to compare with first hand it looks like ordinary indoor insulation to me, should be done with something like Primary Pro, maybe someone else will comment on that aspect. Even the old rubber Armaflex was better bc of its smooth outer surface. (My installer is proposing insulated pipe inside black PVC trunking.) What was the resolution to the warm water coming out of the cold tap?

Might be a good idea to check the voltage drop. IIRC when I had 3.2 kW added to my second roof only 20m distant I got them to wire as two separate 4mm^2 strings to get voltage drop below the recommended 3%. Victron calculator here suggests 6mm^2, however it now seems to lack the volt drop calculation I remember using but other apps are available.