joth

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.

In my experience larger pipework and some degree of zoning would be needed. Most of the year I'd like additional cooling ij the upstairs rooms, even though the ground floor is in heating mode. I guess getting one mvhr per floor would be simplest, although adding yet more cost onto already expensive system On the plus side, at least in my house redoing the FF pipework with larger diameter would be simple enough. (Indeed I've essentially already done that piecemeal, by adding ducted Fancoils and then forcing air from outside directly into those ducts at night time. My own mvhr uber bypass). All that said those are specific challenges hit in our passivhaus retrofit, and regardless of the improvement opportunities I'd fit MVHR again every single time. The system efficiency and comfort while avoiding and moisture/mould risk is incredible. And the reduced dust build up a real plus.

Scratching my head - G98/99 and PV connection is managed by DNOs, not by "the" national grid ("National Energy System Operator"). But also National Grid is the name of one of many DNOs. So does this statement apply just in their DNO patch, or sloppy journalism actually meaning all "grid" DNOs, or has the definition of Nation Grid changed yet again while I was out? A link to the original source press release would no doubt help.

One question is your priority documenting if for quotation, construction, or post-completion maintenance purposes? My experience so far is: - For quotation a comprehensive schedule (Google Sheet) of fittings (type, room, wiring required) is sufficient, and indeed preferable to detailed drawings for the reason Dave lists. - For construction, drawings with plans and where relevant elevation show location of each fitting is necessary, but often sockets and lights gets moved about during 1st and even 2nd fix. - For maintenance, ideally one would also have drawings showing the hidden pipework and wire routing. Realistically this would HAVE to be done after 1st fix (but before walls closed) because I've never yet met a trade that will actually follow plans: often times unforeseen practicalities means they can't, but in all cases they will have their own habits and preference and just do it the way they think it should be done rather than how any plan says it is to be done. And in practice I've yet to see anyone actually create such plans: there's too much rush to get started on boarding. These days your best bet is some comprehensive photos (360degree camera is ideal) of every surface of every room. The exception to all the above is if you're literally doing it all yourself in which case you can control a lot more!

Plug PGSPDY2 requires tool TRCSPDY3 https://www.speedy-rj45.com/cat6a-shielded-feedthrough-plug Plug PGSPDY3 requires tool TBSPDY2 https://www.speedy-rj45.com/shielded-plug-for-xl-cable Well that's not confusing at all 🙄

I've typically bought from https://bownetcms.co.uk/ as they had fairly good pricing on CAT6(a) too, but I haven't comparison shopped this for a few years. Make sure you have the correct compatible crimping tool. And buy some spare blades while ordering ... And remember to use the little plastic carrier to arrange the cores correctly before pushing them through.