joth

For an a2a system, yes definitely. For a2w I'd recommend provisioning for it if it's not too difficult, but in practice I'd always run the water flow temperature above dew point so the condensate is not needed (and actually just creates a liability of drying out and creating bad smells)

Define "effective". If you leave then running long enough, and ideally predict very hot weather and "get ahead" by starting cooling before the house is already overheating, they're extremely effective. It's what I use, and would happily specify in any build I'm doing the controls for. (But, i know i can do the work to make the home automation keep on top of the cooling demand. You don't *need* automation for this, but it takes a bit more proactive user intervention. I can't rely on the occupier being so diligent, and they may also do stupid things like leave shading up and open the windows when the outside temperature is hotter than inside) If you're more into waiting until it's unbearable then smashing the A/C into max, you need a2a AC.

It depends a lot on location (installers in expensive property areas charge more - somewhat justifiably as they no doubt have higher living costs themselves) However I'd be very surprised if you pay someone to supply & install A2W, UFH, 5 FCUs (and a DHW tank right?) for less that 15k. Not in the south-east, for sure. When I tendered my reno (in 2019) my builder quoted 8k to install just one ducted FCU on its own - without any A2W or plumbing work! That was obviously a throwaway quote for work they didn't want to take on, but still... FCUs are still not much loved in this country. If you do non-ducted / wall mount fan radiator it's probably a bit less. A decent bit less if your installer prices it as just another radiator install. Cheaper to install, cheaper to run, or ... ? If self-installing it's almost certainly the cheapest way to get heating and effective cooling. I contracting out, too many variables to say Running costs - probably the cheapest option, considering reduced maintenance load vs 2 systems, and esp with the increased TOU shifting that UFH allows. I'd always say put the UFH in, if you're doing some sort of GF slab that would accept it. Even if not connected it gives so much future flexibility. Specifically, UFH in a well insulated slab is both ideal emitter for renewable heat sources (very low flow rate), but also doubles as a large heat battery (storage heater) so you can heat it up during cheap rate and coast through the peak period. A2A really can't do that .

Maybe of interest to some people here, that would like to be on modern TOU tariff but can't get a smart meter due to lack of DCC coverage https://www.ispreview.co.uk/index.php/2026/06/chameleon-tech-uses-home-broadband-to-solve-uk-smart-meter-connectivity-woes.htm Technically not that different to what the Octopus Mini has been doing for a few years, except it sends the data to the central DCC so is supplier independent. It will continue working when you change energy supplier. Sadly it also lacks the handy MQTT interface of the competitor Glow Display IHD+CAD. There are some fairly absurd consequences of all thise: 1/ Despite being electricity supplier agnostic, this will likely break when you change internet provider (due to this industry wide failing that for most people, changing ISP changes the WiFi access point and changes default credentials to that WiFi) 2/ A rural property might: - fail to get coverage of the national DCC (despite gov funding to build it and a big drive for smart meters) - fail to get wired internet (despite gov subsidies to rural areas, and building regs requirement to prepare the house to receive it) - fail to get terrestrial wireless 4/5G coverage => Ultimately have to fall back on a foreign owned and controlled satellite internet provider to connect their smart meters to the supplier. Lets talk again about critical infrastructure sovereignty.

I connected mine from softened water, because that's how @Jeremy Harris did his. (His reasons were to avoid cost of another descaler ,and it makes a better cup of tea, IIRC) After 5 years I've not had any issues with it. Ours is a combi tank so the main kitchen tap is all softened, and we have a dedicated hard water spigot next to it, mostly used for cold drinking water We're in a fairly hard water area - borderline for being within the safe guidelines for drinking the softened water. If I have four mugs of tea (1L water) it's about the same as one bag of crisps. If someone has a medically prescribed low-sodium diet then they should avoid it still.

It's relevant for any external pipework. I think this is more common in F-Gas installs as they tend to be retrofits (in domestic installs at least), and tends to be easier by running pipes all over the outside of the building. (Ugly for sure, but easier & cheaper). I expect retrofits to increasingly use a2a for this very reason. This is the key decision point. If you're happy to pay for it, then an a2a (i.e. some sort of refrigerant based) system is the only way to get the "arctic gale" of an aircon system. Whether you combine one system with UFH & DHW or do two systems (potentially one exhaust air for UFH & DHW) comes down to shopping about, supplier selection and what they are comfortable working with. Cost wise it's probably a wash (one complex system vs two more conventional ones). A a2w heat pump with FCUs is likely cheaper to install and can perform very well (comfort and cost wise) if setup correctly. And is much more DIY-able if that's your truck. But it will never give the same frozen air blast of a2a

If you ask OpenReach they'll tell you only they are allowed to move the master socket. That detail aside... I'd say what everyone else said. Wrap some electrical tape to insulate the wires from each other before pulling back out through the wall. Else if they short they'll spark rather worryingly.

I have a Texecom Premier system, professionally installed, and honestly I can't recommend it. It's hugely antiquated. I posted a short-list of my grumbles with it on the Loxone mailing list 5 years ago -I'll copy below for posterity... The key question is do you need a "Graded" alarm system? this is never financially worth it for "insurance premium savings", the monitor/support contract costs more than the savings. It's really only worth it if you have high value items that the insurer refuses to cover without a graded alarm. Or, you just want the highest level of system for peace of mind. A graded alarm allows for automatic police notification. I found that a waste of time, as the ARC would call me and my 2 other keyholders before doing police callout, and if anyone answers they would basically just say "your alarm is going off" and hang up, no information on what cause or support in figuring out if it's a false alarm. Which was oh so helpful when I was camping on a mountain in another country... So I've now terminated that contract and do my own self-monitored alarm (via Loxone, and a network of mutually supporting neighbours) which is cheaper and far stronger protection. If you DO need a graded alarm, I keep hearing AJAX.systems is the much more modern system, and uses cameras for much stronger confirmed alarms. (Texecom has a camera offering now but honestly I wouldn't touch it given my experiences) Still looking for some first-hand feedback from someone that's lived with AJAX for a few years and see if it lives up to the marketing.

The SolarEdge modbus interface is not great - presenting scalers as value + exponent in separate registers is inherently racy and can create large glitches in readings. I extensively hacked the Loxone integration to work around this -- basically read multiple registers in a single atomic 64-bit register read, then crack apart the words and recalculate the correct values. BUT it's still better than their very low frequency cloud API. What do you mean by At the moment still time based?

Seems like the research was published in January but a load of AI regurgitation has sprung up about it in the last few days. Original paper https://www.nature.com/articles/s41598-026-35389-6 Not sure, the reference "problematic" LEDs in the study were 3000K so it's already comparing incandescent vs warm white LED. Skimming the article all LED lights roll off at about 670nm but you need about 1000nm+ for the IR spectral component they talk about I've always felt the CTT [colour temperature tuning] is bit of a fad, especially in a domestic setting. But I can see a variant having a large benefit of having WW / IR dual channel emitters, and dynamically increase the amount of IR emitted based on various factors. e.g., more IR in winter when the inhabitants will have exposed to less of it naturally, and also when the loss of lighting efficiency is not so problematic as the IR is at least contributing to useful space-heating.

And down-sizing the ASHP to allow these long runs at a low deltaT without short cycling, isn't it? Our ASHP is way oversized so will bordering short cycle (5 min runtime, 10min period) when just cooling the slab to ~16deg. I'm still getting COP of 3.5-4. But it's powered from PV - if I could double the COP it would give me about 30p more SEG payments per day on these hottest days.

This is how I set mine up (6 years ago) on our ecodan, the problem is it's not just the FCU loop that needs condensation proofing but also the primary pipework that includes the filter, pump, sensors, divert valves etc. None of those devices are designed for being insulated, indeed there's a risk of pump burning out if you really did, and they gather condensation as easily as the pipework. Adding a second, much larger, FCU and keeping it at dew point is how I've used it for past 3 years.

Yeah by hot i mean "not cold", c.f. typical (historic) uk climate averages: 15-35°C is the ideal temperature range for LifePo4, which is much hotter than the uk average of 10°C

It's an interesting trade-off, as batteries like it hot and this move will reduce the efficiency and lifespan of the batteries when used in the cold, in winter. If you're only using them for PV self-generated storage, that's probably moot, but if like me you fill from overnight cheap rate then it's rather a hit. That said with 27kWh you have a lot to play with. I hadn't realised batteries could generate so much heat - presumably you moved the inverter too, and that was the actual heat-source? Unlike batteries, inverters do like it cold.

It's not so useful if you want to add on automations of any type - even a button to "turn off all the lights" is much trickier as it needs to inspect the current state and only pulse those that are on. Depends on what the end goal is really

My go-to is the Waveshare 32ch modbus RTU relay - been running a a few for over a year now, very stable. However i can't see evidence of CE mark now. Not even the old incorrect kerning "China Export" variant

Final follow up on this L9 error: it was not (really) the flow sensor or the kinked up flexis, but a load of limescale build up in the ASHP heat exchanger. Full write up in new thread:

OK early signs are (very) promising! the "bucket test" delivered 24 l/min, and I've refilled the system (adding a bottle of F1) and it's now doing a DHW cycle at 16 l/min. Still not quite where I'd like it to be, but far better than the 10 l/min or less it's been hobbling by on for the last 24 months .... Interesting... I'd always thought using such occasions as an opportunity to flush out the crap and refill with clean. But yes, or course ... if scale is the problem refilling it is introducing a whole load more calcium carbonate ontop of what's already built up. I guess running the drain off through a fine filter would help sift off the worst of the mess coming out. Challenge is where to put the 100l of water when temporarily draining down the system ... although in most cases I can isolate the volumizing tank and leave the UFH loops untouched, so probably a quite doable. I'll read the heatgeek page and ponder how to attack this next time I do some service on it. Good news is I do now have this nifty wee pump so cycling water through it is much simpler now. 15 quid well spent https://www.ebay.co.uk/itm/187759301764

Thanks @JohnMo that's super useful info Today's project will be just to descale (the second batch of DS3 is currently resting in the PHE), flush, flow rate test, lob in a bottle of Fernox F1 and set the system going for a few days to validate I'll definitely look into the VDI2035 for a follow up project once the basics are back working

- Probably nothing ASHP specific about this question, but I'm specifically asking in relation to an Mitsu ecodan 8.5kW ASHP - This is the next instalment of my ongoing debacle about flow rate errors, link below. I now know this is not a sensor or plumbing error, but the plate heat exchanger is completely blocked and needing clearing. My plan is to get pickup some Fenox DS3, mix it up with hot water and pour into the PHE. Obviously with the whole lot disconnected from the primary circuit, and using appropriate PPE. Then flush it all with mains water. If that doesn't clear it up, then I probably need to get Mitsu in to replace it. Interested if anyone has had similar problem and how they attacked it?? ======= More background: 1/ original post 2 years ago, thinking it was flow sensor error, then thinking it was kinked flexi pipes. 2/ Subsequent update: I bought a cheap submersible pub (Makita LXT powered) and did some simple flow tests into a bucket: - without the PHE inline: 35 l/min - with the PHE inline: 4.5 l/min ---- just a trickle, and critically less than the 5l/min minimum required While flushing it through I initially saw plenty of white-ish sand-like granular dirt come out. Odourless. Presume this is limescale debris: - We're in a very hard water area; originally (2021) the system was filled (by others) with softened water, but since then I heard that's not advised so on subsequent fills I used mains water and Sentinel X100. It originally had glycol but I've never bothered to refill that. It's been emptied and filled numerous times due to FCU and volumizer additions, as recorded elsewhere on here. - It has a Fernox TF1 filter, I've regularly cleared and flushed that but never had significant dirt come out - but perhaps a bit of grains of limescale thinking back. My hypothesis now is that this was always the issue, but every time I messed about replacing flexi-pipes and blowing out the airlocks, I was also dislodging a bunch of limescale each time, but it's still had a constant build up that needs to be properly descaled.

I ran condensate drains but they're always dry because I run it over dew point. I did run it (much) colder for a season, but the condensation on all the plumbing gubbins was too much. Pipes are easy to insulate, but circulation pumps, 3 port valves, magfilter, flow sensor, etc not so much. It quickly started to look a real mess. Adding a second (much larger) FCU greatly reduced the need to run at such low flow temp

We used some uplighters from phos https://www.phos.co.uk/products/uplights Excellent build wouldn't hesitate recommending them as a manufacturer, if you're happy with the price, but honestly not sure I'd bother with uplighters indoors if doing it again. Tricky to install, have caused numerous maintenance issues (floor boards settling skewing them, doors settling catching on them, bare feet snag on them), and the actual lighting effect is often missed other than the occasional blinding of eyes when walking over them

Yes! We talk a lot about renewables requiring grid reinforcement, but in many cases renewables *are* the grid reinforcement. Especially if a battery is also installed at the far end of that long bit of wet string.

Fair point 🤣 What I was trying to say was it would be unnecessarily complex to try and design something elaborate into the standards requiring "intelligent" collaboration across a system of inverts communicating with each other, when you can achieve it within the existing pretty dumb standard.

In principle it's quite easy, unfortunately the grid would need to be re-engineered. It's also unnecessarily complex, from the grid operators view. Scaled over 10s or 100s of houses, the current system of individual inverters just shutting off when hitting the threshold has the system wide effect of gracefully reducing the amount put into the grid (as each inverter shuts of one by one, converging to a stable number exporting during periods of strong sun and low consumption). It just sucks for the individuals that get hit by it first as they don't get to self-consume any of their solar if the inverter has safety shutdown. What can be very frustrating is if the inverter is on a long AC line within the property (after the meter) then it may see >253V even though the grid itself outside the property is no where near that. It would be tempting to say either allow the inverter to exceed 253V so long as it is export limited (to zero export) or if there's a voltage sense at the meter tails. Of course, this is messing with a safety system, and also risks damaging other equipment in the home if that starts seeing > 260V, so a terrible idea in practice. The answer here is move the inverter as close to the meter as possible, and ideally have dynamic export limitation (to do near-zero export when it sees the grid is over 250V) and then it will never need to trip over 253V while still satisfying the home's own demand. A DC-coupled battery also helps capture what would otherwise wasted solar, oc.