joth

Current thinking is to run accessible conduit to all switches I can, and pull cat5. For those I can't duct it'll be T&E *and* cat5, for future flexibility Ideally, light switches should have a neutral now anyway (if you want to allow for future use of wireless switches) but 3+E plus cat5 is starting to get ridiculous...

Personally I don't see much point in radially wiring mains sockets purely for automation. I'm putting double sockets most places, and chances I'd want both to turn on and off together is very low. I'm ok using plug-in automation for those where I do want it (sonoff, tuya etc). I'll still use radial circuits rather than ring final, just for preference reasons. Lighting is more of a pain - I hear you. I'm planning to self installing loxone. It is still possible to DIY loxone, although they're actively pushing enthusiasts away and trying to refocus themselves as another control4 competitor. So it's not something I'd strongly recommend. Radially wiring each light fitting does mean it's quite possible to convert to a dumb control system, although some rooms it would leave secondary lighting rather orphaned (switch boxes not large enough for the number of circuits needing control). In theory KNX is the true standards based wired solution. Some countries even call for it in their building code. But it's inexplicably expensive parts, and infuriatingly obscure to programme, so very much a high end luxury option right now. Rako is a DIY friendly wired lighting system with open price list you might look at. Main drawback is their automation API is antiquated and lacking in key functionality (basically it's write-only, no way to read back the current brightness of a dimmer)

I'd be wary of this because DMX is intended for a daisy chain rather than star topology, and has a limited line length. Long runs can become very intermittent and tricky to debug. For this reason I'm putting almost all my DMX dimmers in the central cabinet and radially wiring a star topology of 1.0mm2 T&E to each fixture. I'm somewhat reluctantly using mains level dimming just for simplicity & easy availability of the bulbs, however I'd probably use DALI if wanting to put the dimming drivers near each fixture. On the plus side wiring the mains radially does make it easy to switch to a dumb lighting design. For a few places I'm using low voltage leds I will probably put the 24v dimmer next to the led strip and use a DMX amplifier/splitter to keep each of the runs isolated from each other. The whole market is pushing wireless systems more an more, even for new builds, so doing wired install in a retrofit is going against the grain.

It's a bit love hate with loxone. Ideally I want something non-wireless, standards based and I can fully install and service myself, but have the option of professional support if needed. Loxone is closest to that, but they're slowly pushing DIY installers away and going more proprietary. Ironically it's the lightswitch aesthetic that pushed us to them, as I had strict instruction not to have something that looked like an office conference room controller and honestly loxone are the only ones that look like a residential switch to me. I'm using home assistant for anything heavyweight and keeping loxone for the core "mission critical" stuff like lighting and heating. Aim is the house should still be broadly usable even if the IP network and every PC and RPi crashes or is turned off.

I've been using Chrome remote desktop quite successfully to connect to my Windows box, you can try that if Microsoft's own product is nobbled not to work on the free ed OS? I'm similarly doing this to access the Loxone Home automation designer software. I understand they have a Mac OS version of it too now. And the SW is one thing they don't charge for (and it's not terrible either).

As initial validation of this: the Luxpower hybrid inverters (as referenced several times by @Jeremy Harris) have the stage1 trip set to 262.2 V, and stage 2 way up at 273 V, according to their G59 test report here (table 13.8.3.2, page 15). OK OK looks like this might have been a red-herring, Solar Edge sending out misleading info to our supplier or something. At least, I found the G99 test report for the SE8000H and it states that stage 1 trip occurred at 262 V and stage 2 at 274 V, and it can operate at 258 V for 2s without trip, so from that data it looks a lot more viable. Just need to get their tech support to confirm this.

Bed 2 seems very generously appointed with wardrobes? If they're not all needed, you could allocate a bit more of that double wardrobe space into Master bedroom, moving it's entrance up onto that wall (maybe making a dressing room, if you like) and in exchange give up some of the top-left side of master bedroom to open up the stairwell over the hallway below, possibly even vaulting it up to the roofline (depending what your doing with the roof, and your appetite for inaccessible skylights) It's a trade off of useful floor area vs an element of wow factor. btw I'm always impressed when architects use 'up' and 'dn' to label stairs, given their rotational symmetry

Yeah, my mind spins both ways on this: if these sunny times are rare occurrences, surely I want to maximise them as much as I can!! but you remind me of a good point: maximizing peak output is not necessarily going to dint the overall seasonal performance so much. One thing I do like about the Luxpower is I can easily see a path for getting a minimal system installed, and then incrementally improving; adding more batteries, or even splitting to 2 inverters if we really found it would be justified

Key reason for this is most houses (even those built to current regs) are drafty and have too little insulation. Result is people leave the heating off as long as possible, then when a cold snap hits they want instant heat everywhere. This is compounded by having too little insulation under the slab meaning it's just as easy (or easier) for the UFH to escape down into the ground than up through the slab. The decision to have a large heated slab (be it concrete or a decent thickness of screed) on top of UFH is often coupled to having a very well insulated house everywhere, and especially good levels of insulation (150mm min, up to 300mm often advised) under the UFH. This means heating can be left on year round, just driven by a room-stat to keep the whole house at a constant temperature. This way you're never trying to heat the house back up from cold, and so the time it takes for heat to come up through the slab is largely irrelevant. (And as you say, provides additional benefit) What insulation and airtightness standard will you be aiming for? This is what we wanted to do but our architect and SE weren't open to considering it. Our local building control messed us about with the slab enough as it was (we're renovating and extending a 60s build; originally it was signed off with a raft foundation for the extension but after it was dugout the BCO had a change of heart and wanted strip founds dug) so in retrospect I'm glad we kept away from doing anything more ambitious on that front. We have 100mm concrete, 160mm Celotex, 75mm Screed (embedded UFH), which for us is enough to meet EnerPHit+ standard and hopefully give us some reasonable thermal mass(TM) but on the low side compared to most on here.

Yes, I think it is really. It would mean we wasted about £1500 moving the existing supply on top of the £3000-odd for the new one. Moreover, we'd also need to create a new place for the meter (the existing was allowed to remain indoors as it was already there, but a new supply has to go externally) and so potentially re-dig all the trenches for that, and likely a 6+ month delay given UKPN would need to close the road to make the connection and that seems really hard to do because of the school. (Cadent charged a pretty price to do this for the gas permanent disconnection, but in the end I think they gave up trying to get the permission and have just left it with a "temporary" disconnect just inside our boundary). But I agree, I would have gone with 3ph had I realized this back in January. When you ask for practical examples, you mean of inverter cutting off from being overvoltage? In the UK, my neighbour and @Jeremy Harris are the two I know of.

As initial validation of this: the Luxpower hybrid inverters (as referenced several times by @Jeremy Harris) have the stage1 trip set to 262.2 V, and stage 2 way up at 273 V, according to their G59 test report here (table 13.8.3.2, page 15). Given that this hybrid inverter costs less than the SolarEdge (even without counting all the micro optimizers), and gives option of battery storage for only the cost of the batteries (which can be incrementally added), it's starting to look a very attractive alternative. The main drawback is while it can handle 8kW of PV, it only has a 5kW inverter, so once the battery storage is full we'll be losing 3kW of generation. (I'm assuming it can dump 3kW to batteries at the same time as exporting 5kW via the inverter). So to minimize that wastage we'd need to buy LOTS of batteries, or get 2x 4kW inverters, either way pushing the price way back up again.

Good to know! The replacement I doesn't have an arrow which is what was misleading me.

I too might be in this position. The house is specified to have full A/C - it's always good for soaking up a bit of spare power. Can always open a window to make it work harder... Interestingly I just found this: https://shop.gwl.eu/docs/web/2018/EN_50438_2013-BS.pdf Section "A.12 GB – United Kingdom" (page 31) clearly shows the stage-1 overvoltage protection for the UK only starts at 262.2 V (with 3s delay) and stage 2 is way up at 273.7 V. SolarEdge have said (via our supplier) their inverters cut out at 255 V (presumably with ~5s delay) and hard cut off at 262 V, i.e. designed for European market, and there's no way to adjust these trip-points. Time to look for alternative manufacturers, it would seem! [I'm probably derailing the conversation here - I know the grid over-voltage issue has been mentioned many times but I can't spot another sensible thread to put this on?]

Rereading this now having messed about with it more, I think the leaking one could actually be an automatic pressure relief bypass? At least, it has a directionality arrow stamped on it, which only makes sense if it is, right? And it'd make far more sense than just a straight isolator there. Anyway as I've wedged the zone value open this should "never" need to open now (famous last words?) Yup you were exactly right on that too !

Thanks @PeterW ! I did glance briefly at that big coupler but figured the isolator only started leaking after I tried fiddling with something I didn't understand and I didn't want to make yet more problems for myself trying to fix this one ? I've wriggled the isolator screwhead repeatedly and somehow got the dripping to virtually stop, hopefully that holds but if not this definitely looks the simplest way to remove it all, at least for someone like me with a irrational fear of cutting and joining water pipes. (so weird, I find electrics trivial in comparison)

Small update: Well, I bought a new isolator valve today from the shop at the end of the road. Couldn't bring myself to pay Toolstation £5 postage so instead paid £6 for it locally!! Managed to get the compression nuts undone off the old one but not enough slack in the pipework to allow me to pop it off the pipes. Olives solidly jammed in place, so no idea how to get it out to put the new one in? Anyway for kicks I tried the rest of the plan: forced the stuck zone valve open as best I can and rewired the wiring box to bypass the zone motor, connecting cylinder stat return directly to the call for heat (brown to orange). Refilled system and bingo we have working hot water again, and a slow dripping bypass valve. Current plan is to let it drip in a bucket for a couple days and hopefully the calcium will seal it back up ? Otherwise, er, I'll have to go at it with something more brutal. Presumably hack one olives off to get enough wiggle room to remove the valve, and hope I can get it reassembled. Really wish I knew what purpose it serves though??

Microinverters are convenient (maintenance wise) placed inside the loft, but should be as close to each panel as possible (ideally just using the short retained flylead that comes with each panel, no extensions). This is awkward if doing a "warm loft" as it means lots of penetrations through the thermal & airtight boundary on the pitched roof. For this reason we're doing micro-optimizers on the back of each panel, then we'll chain them to have high-voltage DC connection to the ground-level inverter.

Even with 3 phase it would need permission, being over 11kW ? I'm in a bizarrely similar situation of wanting to limit export, not just because self-consumption is more £ efficient but because it will push the local voltage over 253V and shutdown the inverter. At times of high PV generation I might literally be better off (financially and in CO2 footprint) by running a pointelss convection heater in the garage or shed than having the inverter shutdown. I SMH at how we've ended up with such contradictory regulations & incentives.

I was curious about this. On 3 callouts (2 companies) that's the only explanation given (weell, alongside "the whole system design is a mess"; I think the boiler was moved at some point and resulted in a web of piping) I'm not in a place to defend it either way. ¯\_(ツ)_/¯ Probably. While the loft is littered with discarded inhibitor bottles, it's bound to have been skipped on some occasion. (But isn't radiator water always black...?) Other factors: - we have very hard water, 312 mg/l ... - I think the house was left empty for a while (probate?) so that tends to be when the seizing up sets it.

OK. I think it was my inherent hatred of these screwdriver driven isolators reinforced by the thing squirting hot black water the moment that touched it, plus suspicion I didn't even know why it's there (when would you open it up?) that made me just want ride of it. So I was wondering if these more reliable for my level of plumbing skill, but sounds like a direct replace is the way to go. Great tip on the LS-X too... that sounds like magic paste. OK - it's really stiff to move the valve tap. The gas check plumber was reluctant to to force it and said it needs replacing to get it open, I pushed a bit more and think I got hot water to pass through it (before I made the other leak and had to drain the system.....). but I fear it is only part open and liable to close again, if they can do such a thing? When I took it off, it made some horrid grinding noises, got really hot, then when I poked it it went, sort of like, "twang" Ah, thanks! That's exactly what I did then. I did poke it a bit more to try and re-engage ... but now have a collection of loose springs, a corroded ratchet gear things, and a motor that gets hot and angry (but surprisingly silent) if powered up. The thing I probably didn't make clear is this is the third time this valve has stuck in about 6 months. The previous tenants had a plumber in to unstick it a couple times, and then when it got stuck again in March for us I just said stuff it let's use immersion heater (having DIY repaired that, which I'm quite proud of all told) :-) The root cause is suspected to be an existing leak that is drawing the air into the system and hence blocking that valve. Two plumbers haven't found it and just said they'd need to replumb the whole damn house to be sure they'd fixed it! So if I can jam the valve open, I'm reluctant to replace the motor as all it will do is close the valve and then that will inevitably get stuck again... if I can jam the valve permanently open then we can then use the system for DHW. Thanks!

I'm being a cheapskate - it's someone else's home and they're going to demolish it and the end of the year so just wanting the minimum needed to make DHW work again. There definitely is cost/effort trade off I'll grant you.

Backstory: I'm renting a friend [and fellow self Builder!]'s house while ours is renovated. Due to COVID delay now looks like we'll be here through to the next heating season so thought it worth getting a gas service, and see if I can get the DHW working again. There's been a long standing issue that the DHW zone valve gets stuck due to an airlock (presumably because of some unknown slow leak somewhere) so we've been using immersion heater for 2 months. The gas man wanted £300 to drain the system so I said stuff that I'll do it myself. The whole house is in line for demolition, so not worth spending much on, this is all Acme Bodgit & Scarper land. However, in my eagerness to investigate I touched a bypass/isolation valve of unknown purpose, that started to leak (video) and dripped all night, so I've now drained the system and am enthused to learn how to solve this, as it is good prep for when our own install happens later this summer. Here's the mess (closer up). And here's my attempt to label what's going on: Plan of attack/ question: 1/ Remove the leaking bypass valve and cap off the pipes. I believe this valve is closed (?) and I don't know what it's for (it seems to connect flow directly to return, bypassing both zones?). For a minimal working system, I don't think we need it. Q: what's best way to cap it off? It's connecting 15mm pipe either side. 2/ Replace the stuck DHW zone valve with straight pipe. What's the best way to do this? It's 22mm on the right feeding into 28mm on the left side. (I *think* I've just about forced the valve into the open position, but hard to be sure it will stay there?) Obviously this will mean we can't run heating without DHW also running, but that's a fair trade off for "just a few months" usage. 3/ Electrically disconnect the (now burnt out) DHW valve head. This seems to have a microswitch in it that needs to be press if (and only if) the timer is allowing for DHW to be on. I think this is S-plan wiring, so I think I can just use the "motor open" signal to trigger the call for heat directly. i.e. connect the Brown wire to the orange wire, if it is following this diagram? In summary: 4/ Bonus question: how to test all my replacement connections, other than fill it all up and wait? Cheeers!

It's intended for an australian market, but this article is quite interesting. Aside from learning the fact Australia has the exact same 230 VAC +10% -6% requirement as the UK (wonder how that came about...) they have a few more options for recourse- it seem the rules over there are that if the grid is just at 252V but your local observed voltage is rising above it due to the inverter (and a long cable run from the grid), you can seek permission to set the inverter's trip points slightly higher. This is called Volt-VAR mode, perhaps named after California "Rule 21 Volt-VAR requirements" Another option (both there and here) that some people have been sold up to is installing a so-called voltage optimizer (examples: PV+, EdgeIQ) which reduces the local voltage as seen by the inverter. I truly can't understand how this is morally any better than going and fudging the voltage trip-points in the inverter to be +10% higher, but still these things seem widely recommended upsell by PV companies so I presume they're at least legal and maybe even effective. (They're only good for 4kW though so no use for our planned install.) Finally, perhaps the most practical suggestion is to go for a 3 phase supply from the grid to reduce the local voltage increase per phase. Damn- wish I'd thought of that 4 months ago :-(

Many folks on here get by without any heating upstairs (including some that installed it but find they never need to use it). This is what we're planning too, but with some future proofing so we can easily add panel heaters or blown hot/cold air if needed in future. It depends on exactly how much insulation and airtightness the building has as a whole. Are you planning to install MVHR, and have you had any thermal modelling/heat load estimate made? If not then @Jeremy Harris had a helpful spreadsheet that can be used to get a pretty good estimate.

A few more unorganized thoughts on this: - the key point of a buffer tank is to simplify commissioning, making differing flow rates compatible. Do anything clever and you've added rather than removed complexity. (Tripley so is using SA as buffer tank) - I've understood the uvc is in the loft, but does the buffer tank need to be there too? Putting it nearer the place that needs heating would be more intuitive to avoid heatloss. This will probably payback much faster (I'm reduced heatloss) than incremental gains on COP for the DHW) - if ubc cold-start reheat times are critical, what are you going to do in summer when the buffer tank is not in use? Maybe consider a larger uvc and don't let it get empty? - with uvc in the cold loft, insulation on it will be important. This maybe of interest: https://www.osohotwater.com/en/domestic/optima-geocoil A rated with "tank in tank" integrated buffer tank. - will you be using a monobloc heat pump? We're putting in a warm loft, but went off putting the UVC there because of the pipe run length to get to it.