Ouch, that sucks! You might want to change the t-stat batteries every fall just to be sure. I'll need to check my RO room today, but I have 2 forms of heat in there. 1st is a direct vented wall heater runs on propane, off a bulk tank, it has a standing pilot. If that fails I have an electric heater set to come on if the temp drops to 40 F. So far no issues. The propane heater I use is called a "Housewarmer" and it is only 8000 BTU, which does a fine job.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.