ville,
“first line on log is 4.361” — I have seen this in the distant past, maybe release 23, Firmware 1466039460. It was unrelated to thermocouple. James suspected the firmware watchdog timer issue. It was fixed in later releases and now it must have returned.

Also, I thought James said logging and graphing were never intended to be performed together.

There is lots of good historical info in this forum, but I haven’t found a good way to search it. And relying on my memory is…well…I forgot what I was going to say. —- Duane