Radian

They say this kind of thing but then bugger off for a couple of months IME. Perhaps ask flooring mfr. what they think, get answer in writing...

Until you want to do some basic module testing ?

OK, right, I couldn't spot any cabling other than PV in/out when I looked at the datasheet. Does this then mean there's an ID on each optimiser or maybe the discovery is performed using a unique MAC address per device?

Our extension's foundations were poured in 2019. The blockwork was completed in 2020 with floor screed and wet plaster finished in April that year. It went all through the summer of 2020, and 2021 - by the end of which RH levels were still up as high as 80%. I got fed up and bought a dehumidifier which has been running constantly ever since xmas. 3 Litres a day is still coming out. But outdoor humidity is currently in the 90's so I don't know if its a massive air leak or just still drying out. I think the latter because the attached garage does occasionally drop below 70% So yes, there's a stupid amount if water in the fabric of new buildings and it sticks around for years.

Most if not all inverters use MPPT per string input but I think outboard optimisers can compensate within a string to get around partial shading. I'm not a PV user though so I may stand to be corrected. Also, thinking about the testing suggestion I made earlier, it occurred to me that I would be possible for back-channel comms between the invertor and optimisers on the DC connections (when I asked how they might know if they were connected) if the signal was AC coupled. I'm doubtful that this would be the case but it might explain why Solaredge sell an adaptor designed to allow their optimisers to work with other makes of invertor. That bit was what got me thinking.

I recently bought a 3-pack of these <£5 each. They took a couple of weeks to arrive from China though. Of course I don't know how 'hacky' you like to get but if you're into coding then the great thing about these is that there's an alternative firmware you can apply that exposes their readings as BLE beacons that can be picked up by HA software or ESP32 Bluetooth etc. I use this to log values from 10 of these to a database via node-red. May not be your thing but I know some people here might be interested.

Solaredge say "As long as the power optimizers are not connected to the inverter or the inverter is turned OFF, each power optimizer will output a safe voltage of 1V." So how does the optimiser 'know' it's not connected? (excuse my ignorance but I think you should be able to hack around this problem with a few clues). Presumably the optimiser's output current sense is used to inhibit the MPPT logic. If this is the case then applying a suitable load should get it to operate. Guessing that your 245W panel has Vmp of, say, 44V then you would want a load current of 245/44 = 5.57A So a resistor of 44/5.57 = 8 Ohms would present the optimal load. That might be a bit tricky as a dummy load sinking 245W (loudspeaker was my initial reaction!) but a couple of 3kW kettle or immersion heater elements (240V/13A=18 Ohm) in parallel would give you an idea of whether the MPPT function was operating. A multimeter would be able to confirm your load resistance of around 9 Ohms, and show if around 5A was flowing.

Turns out superfoil also have a single-ply breather membrane (like Tyvek) called SFBB but it's not shiny ? Apart from that I guess it's exactly what I wanted. But not sure how 'maintainable' the surface would be.

I just found one more properly breathable blanket style product Superfoil SF19BB This one has a few more layers giving a reported R-Value of 2.2 so roughly equivalent to one 100mm layer of rockwool. It's a bit more expensive than the YBS but more insulating and a tiny bit more breathable at 0.115MNs/g Annoyingly I also found exactly what I want - if only it really were breathable: "Vapour Barrier & Waterproof breathable Membrane" must mean air breathable? After all, if it's a vapour barrier then what's it breathing? Air sans water vapour? I guess that might be possible but from the look of it nothing's going to get through. I just love the customer Q&A on this very point: Very helpful ?

Yes, this is an area I'm currently looking at making improvements in. My understanding is that a ventilated loft such as mine should retain an open path for water vapour coming up from the house to be naturally extracted with the regular air changes in the loft. I would hazard a guess that the majority of the UK housing stock is like this, certainly in houses built pre 21st century. I'm quite sure these non-breathable products aren't aimed at the EnerPHit or passive house markets but they are certainly the cheapest forms of insulation on sale. This will have plenty of people, unaware of the issues, installing it and creating problems with rot and water damage. I think this would be irresponsible. However, this product caught my eye because I'm considering investing £630 for 6 rolls of YBS BreatherQuilt 2 in 1 Multi Layer Insulation Blanket which has a very low vapour resistance (0.15MNs/g) to drape over the top of 300mm rockwool to give me a maintainable surface and boost the total R-value a little. Just a little... ...I really only want the perforated foil layer as the r-value of this blanket is 1.6 whereas the 300mm rockwool underneath should be around 6. And I suspect that when laid flat the blanket drops to more like 1. However, I'm not having much luck finding just a reflective breather membrane that is significantly cheaper than this blanket. I guess I could just use Tyvek but I'd rather it was shiny because "shiny is practically the same thing as useful"

No, 6 layers of something

Aldi are currently slinging "airtight multilayer foil insulation designed by SuperFOIL with the DIY customer in mind" According to the SF6 data sheet its Water Vapour Resistance is 1200MNs/g which makes it vapour tight in addition to being airtight. I understood that this was a no-no in the kind of application they're pushing here? WIth an R-value of just 1.9 that's going to be a cold surface for vapour to condense on. Am I missing something?

That's exactly what I was wondering. Knowing outdoor and indoor RH and quantity of water condensed could be all that's needed. ?

Not sure what calculator you're referring to but from tables of Saturated Vapor Pressure, Density for Water vapor we get gm/m3 for 100% RH at different temperatures so multiply the lookup by room volume and take the RH percentage as currently indicated. I just did this for a 68m3 room at 20°C (17.3gm/m) @ 50%RH so there's supposed to be 588ml of water that could be condensed out. In reality with a dehumidifier running 24/7 I have to empty around 2L a day. Does that mean the air is being changed 3 or 4 times a day?

How are you setting the top and bottom of the reveal? A pet peeve of mine is that it seems standard to set them perpendicular to the plane of the roof/window, like it might seem natural to a chippy to trim square between rafters. But, depending on height of window, when finished this can steal precious light as we found: I altered the top trimmers of the two leftmost windows to make them horizontal - compare with how it looks against the one on the right which was yet to be modified.

OK so going back to where you pulled out interconnect D (feed to heater) and it still tripped, suspicion was shifted to the other contact on KA6/2 which appears to be the green light. This, however, isn't connected but the wiring between the relay and installer connection area may have an insulation failure somewhere in between. You want the crankcase heater to work so what you might do is unhook the two orange wires (NO and COM) but leave the relay in place (the heater circuit is the black wires between COM and NC). If you do this make sure to insulate the ends of the wires you remove!

I suppose it could just be a coincidence and removing KA6/2 doesn't actually do anything. If it was repeatedly and reliably the case that it trips when KA6/2 inserted then we wouldn't look elsewhere but that doesn't seem to be the case so yes, maybe swap out the RCD for another.

Hopefully that might be useful to maintain a pest free space but when I know a mouse is present I'm always going to deploy the humane trap which definitely works. Since I learned that mice like to run along edges and avoid open spaces I can almost guarantee a catch the first night after setting it up next to a gable wall. I'm sure sufficiently high-powered ultrasound would be uncomfortable for mice but it is easily attenuated by the plentiful insulation materials found in a loft. The higher the frequency the more easily it is absorbed. The problem then is that compared to the cold, wet and dangers present outside - once the mouse feels warm, dry and safe then it's probably going to habituate to the noise as soon as it finds a relatively quieter spot. There is some research on the subject but I can't find any I would trust. The majority of online resources that dismiss ultrasound repellents seem to be published by pest control companies that would prefer to sell you a service visit. If I ever get the time I would be interested to experiment on one of my guests to see their reaction. A bit of code running on the camera Pi could generate an Ultrasound sweep while the camera records the response. If there's a particular 'sweet spot' for upsetting a mouse then this might be a good way to find it.

I think you would find they're the ends of the wires you can see on the terminals of relay KA6/2 and KA5 They basically go nowhere.

Very likely - especially if 12/13 14/15 and 16/17 are all red link wires (can't quite see off edge of photo). If so there are no lamps connected and the mystery remains.

For such a small creature they don't half make a racket! I'll also swear I could hear our latest one snoring when I was working in the loft shortly before we trapped it. I find WiFi cameras extremely useful for aiding the removal of these pests. I have a Raspberry Pi camera permanently in the loft for this purpose. The Rpi Cam Control software has motion detection and I've set it up to notify my phone when triggered. I find with the trap I made I need to get to it asap as the mouse has nothing better to do than chew its way out. These days you can get a WiFi camera up and running for less than £8 each if you don't mind programming an ESP32. Makes for an almost disposable item!

No news on the "green light"? There seem to be three contacts (orange dots below) for KA6 but there are two KA6 and we don't know for sure which are feeding the circuit that trips. By unplugging connector D (green below) you've isolated the heater but it still trips so we shifted our attention to the remaining K6 circuit - the green light. This seems to be connected via the Installer terminal block but may not be fitted. However, terminals 8 & 9 in the terminal block is where its wires would go. See if you can identify any issues there.

Yes I'm already using that to deny the half of the loft that I've already cleared of cluster flies (yes, we've got all the usual pests) And that's why we use the see-saw bottle trap made out of a juice bottle, coat hanger, rare earth magnet and wood scraps. It's extremely effective except for when the mouse gets on top and pushes it closed like it did this time and in a previous year: It would seem more likely to get in at ground level but I've gone all round checking for gaps and there are none. The telescopic vents have grilles that are too small for rodents to get in. Oh, wait a minute - there might be a way in through the gas meter box - I remember it was full of snails last time I looked. They must have got in around the pipe or something and once inside I suspect an easy passage into the cavity for a mouse. Will check!

Yeah. I sure wish it was a warm roof. However, I think the vents have small enough gaps: smaller than fly size. I've checked all round the other soffits and all are well caulked. Just the two valleys seem to stand between me and peace and quiet. Unless it's up the cavity walls ?