Radian

You're probably looking at the temperature of the sky. Point an IR thermometer at the sky and it's generally -20 or less. Emissivity also plays a role in that low emissivity surfaces like metals read lower than their surface temperature because the IR sensors only respond to radiation. You can readily see reflections so you may even be seeing a reflection of the sky.

Something like this inside the case: If so it could be the pump has frozen. Simple as getting a big flat bladed screwdriver and releasing the disc in the centre...

Probably some form of indicator, maybe a neon. Definatley worth checking the fuse. I think its an early Indirect Heat Interface Unit (HIU)

I can't exactly say why, but I still prefer copper. Especially for big bits of CH run in 22mm and 28mm. Next tap I plumb in might be hep20.

There's something a bit odd about plumbing that always makes me put off doing any for as long as possible - until I finally cave in and dig out the plumbing toolbox. Once started, I don't want to stop. Funny that. I think it's a confidence thing, more so than with other DIY tasks.

Our rental property was built in 1986 and had EPS bead cavity fill. The PVC cabling went through it across a couple of cavity walls not least to get into the meter box outside. I've noticed a few tiny marks on the cables but nothing anywhere near causing problems. It's still like this today only there are loads more poly beads in the meter box. Nowadays they bond the beads with a PVA solution to stop them moving about and the better kind of beads have a graphite coating. This is primarily to enhance their R-value but I think it may also prevent contact migration of the plasticiser in PVC. We just had our empty cavities filled with graphite EPS and I asked the surveyor about cable issues and he said it's no longer an issue 🤷‍♂️

3600J is the largest I've seen reported and also seems to be the most common used in the UK. The sky's the limit though. A meter could be programmed to only bill you once a day on average while giving you that whole day to put energy back into the grid and wind your bill back down. But that would break the money-grabbing asymmetry of the prevailing tariffs. That's why I call it a virtual buffer (or sometimes a Joule bucket). 3600J gets consumed in a second with a 3kW immersion plus 600W house load and put back in around the same time with a typical modest PV system. So quite manageable for the diverter. On the other hand, the virtual buffer can be zero if the meter is designed that way. Every cycle can be determined as a nett energy import or export and billed accordingly. It would take some fancy footwork to deploy a dump load in the space of a cycle but it can be done. I think some meters in European countries operate like this. When I assumed 3600J for my meter, it became apparent that it was much smaller as my meter was recording exports where I should have had none. By trial and error I determined it to be a maximum of 900J but I deliberately limit the range I make use of to half of that. The offsets and thresholds are there to mask the inaccuracies of measurements (mostly CT nonlinearity) but an off-the-shelf diverter has to assume that it's dealing with a minimal buffer anyway. This makes it tricky for those that use burst firing as they're committed to 60J (one mains cycle of a 3kW load). Sometimes PWM techniques are used in diverters such as your eddi to get around the one-cycle limit: varisineTM is the proprietary power control technology used in the eddi. The technology enables the output voltage to be very smoothly adjusted in order to alter the power to the heater. The power to the heater is always a sine wave and only the voltage is altered. This control technology is more sophisticated than many other products on the market and the technology ensures trouble free operation with all inverters and compatibility with all import/export energy monitors and electric meters. Yet it still needs an offset because it can't be sure how close it is to the meter's sensing and could be operating either side of the true balance point without knowing. Utility meters make use of revenue grade power sensing circuitry which entails a series connection to the supply to measure the volt-drop across a calibrated resistance. Consumer grade diverters tend to use CTs for customer safety and convenience - hence the inherent inaccuracies.

I see there are also active versions that at least regulate down from 48V to 12V at the far end. That might be a better approach as it would considerably reduce the current in the feeder cable. I was expecting to buy a regular PoE equipped switch for the router end of this link anyway.

I guess it might be OK, switches with a 12V adaptor will probably regulate down to 5V so there's a bit of headroom for cable volt-drops. The cable I'm working with is around 20m so it'll be a bit borderline. But for £7, worth a punt using a spare switch I can probably dig out.

They all make it sound like you're getting/setting precise numbers i.e. 100W threshold but it can't be. The size of the virtual Joule buffer in meters isn't standardised and without knowing it, an uncertainty is inevitable.

Inside? I hope not!

You don't have to waste time chatting. Treat it rough. It's only Linux underneath.

Almost certainly, yes. Could be leaking 1kWh/day at certain times of the year. If they made it an adjustable parameter, you could tune it to your utility meter although that would involve seeing some indication that it is indeed exporting. My meter has an icon of a ratchet and pawl on the LCD that shows "meter running backwards" harking back to the days of mechanical metering. It also has an export register so incrementally adjusting the threshold over a longish period would allow you to slowly 'turn the tap off' until it stopped 'leaking' but this would be difficult if the diverter maxes out occasionally.

There we go! The magic word. Not many options around but the one you linked looks fine. I've never used a managed switch before though, can you just treat them as plug & play if you don't want to use the additional networking features?

I'm trying but failing to find an 8 Port Gigabit Network Switch that itself can be powered by PoE. It doesn't need to distribute PoE - just get its power from the incoming RJ45 so I can locate it in roofspace with no mains. Not an easy thing to Google up because PoE obviously links to thousands of switches that supply power to the ports, from its AC adaptor.

Just ask Alexa to do it?

That's a good anecdote, but I don't want to pay for advertising and that only has to go so far in a decent product. Sometimes the advertising budget outstrips everything else just to push something substandard to market. If you put enough lipstick on a pig... The other little secret about PV diverters is something I discovered when building one: By necessity, an off-the-shelf product won't be able to operate optimally. There has to be a bias towards export to avoid accidental import for a 'one size fits all' approach to the wide differences between utility meter models. It's no big deal but it's a parameter that never seems to find its way into the specifications.

Hi JamieG, Is your house new or did you purchase it off someone? I'm only asking because it seems most BH PH members come here before they build anything. Just being nosey 😄

Damn, beat me to it. I was thinking much the same thing. Reminded me of a Hotel I once stayed at in Bournemouth which had lampshades depicting Western style 'Iron Horse' trains with a heat-driven spinning disc over the bulbs that made a smoke effect. Was only about 9 years old at the time. Loved it.

That's what I was thinking. I'm dreading going back up into our main house attic to finish adding to the insulation for fear of the biological horrors that await. And we were setting humane traps last year for this very reason, but it doesn't stop 'em dying of old age!

That's the solar coil right? Why did your plumber connect the boiler to that?

It's a piss-take IMHO. Their price is based on the value of the return in your pocket hence as energy tarifs go up, so do their price. Nothing to do with the components they're made with. Typical PV divertor has little more going on inside than a fancy 'smart light dimmer' plus a £10 CT.

The brackets don't show because the handrail has a routed rebate for the tops of the spindles and the bracket fits up inside it. At least this is how most off-the-shelf handrails are supplied. Spacers then separate the spindles.

Decking handrail brackets??

Another reason why some of us 'roll our own'. There's a big risk involved in relying on tech companies to keep services going and you're lucky if they provide the exact functionality you want. You should be able to see the parallel between this and the self-build ethos on BH. The wonderful thing about today's technology is that it's highly democratised by the affordability of single board computers like the Raspberry Pi - which have stemmed from the ubiquitous mass-produced tech that goes into smart phones. You can trace the origins of much of today's gadgetry to that particular juggernaut of a global market. I feel lucky to have been interested in computers when growing up at a time when they used paper tape and punched cards as program storage. Following their development has been relatively easy for me because of the modest pace of things to begin with. But there's so much educational material and 'how to' instruction now available that, any chosen objective can probably be accomplished with a little bit of confidence and a great deal of googling. Once again, much like self building.