The device has entered a vaguely quantum state of being both finished and not finished, working and not working, simultaneously.
Which is to say, the heat engine works and I got a correction out of the thing, but it took about a quarter hour where it should be six minutes at the absolute most.
This, I'm thinking it's safe to say, is largely due to the fact that I'm trying to extract useful amounts of solar energy from Germany's north in October.

If I was attempting a design based on oppressive grey and misery I could probably power the entire god forsaken region.

As it happens, however, this is not a problem, as in about three weeks I'll be back in Australia, where I can more realistically expect blue skies, 40º, and ozone depletion.
Roll on summer!

Again!