After two very dull days (my solar system produced nothing) yesterday evening my outside temperature sensor flat-lined all night, even as the temperature dropped. The SensoComfort reported a OT link strength of 0; it’s usually 6. I presume the capacitors discharged; it began waking up again around dawn.
Anyone else seen this before? I would have thought the sensor would stay online for longer…
I’ve read that the wireless solar-powered sensors are nothing but trouble; would it be possible for you to run a 2-core cable to a suitable location and use a wired sensor instead?
I ended up moving the sensor slightly!
I had moved it last Sunday. The installer had put it next to a square plastic down pipe “to shield it from the sun” but the northern wall never sees sun in my heating season, and the sensor was reading a degree or higher than my weather station. So I repositioned it well away from the pipe and, noting that the installation instructions say put it 1/3rd the way up, a fair bit higher.
It worked fine until Thursday. I put it in the sun on Friday morning and then put it back up. Worked fine for a while although link strength was only 4 or 5. Then it dropped to zero again after dark. I took the sensor down and placed it very near the receiver unit (but still outside). Link strength 9! 
Its new, higher position was level with or slightly above the floor of the first floor; maybe the extra material was enough that the 868 MHz signal wasn’t reaching the receiver. It shouldn’t vary as much as it was doing though.
So I moved it down half a metre. I taped it in place first and link strength was 6. After screwing it in place link strength has been 6 or 7. Weird, but seems to be fixed…
That sounds fairly typical - r.f. propagation is a black art at the best of times. Even ½ wavelength is often more than enough.
My myvaillantapp, has done something weird today. It’s showing my data from before my internal PCB was changed and the serial number changed. It’s also showing incorrect current power use figures. Logging out and in hasn’t fixed it, very weird.
I always get nervous when stuff like this happens, that I am going to get electrical issue again with it and the machine stop working.
The vaillantconnet box has a blue light, I hard reset this but it went solid blue again, but the data shown in app is incorrect. Really vaillant software in unacceptably shit for the cost. I’ve unplugged it for now, thankfully the heatpump is working fine.
Hi.
My myVaillant app has now stopped showing the middle lower tab, Energy.
I would suggest it’s a backhaul issue. Fingers crossed.
Daz
Hi.
Just to follow up, the app has now returned to normal. Energy data is all correct. So I presume a backhaul issue. @JamesH I hope your issue has resolved.
Daz 
Thanks. I just went and plugged it back in and it’s working now. Anxiety over.
