Our house is set up on off peak electric ceiling heat with GFA backup. Yesterday, our bedroom heat "stuck" on and ran the temp up to 80+. I pulled the thermostat and found a mess in the box, and some of the wires had insulation melted off. I believe hot was shorted to the thermostat line - bypassing the thermostat. Not positive, though - when I pulled the thermostat out it destoryed any hard evidence.
So, today I trimmed the bad wire back and replaced the thermostat for good measure. It doesn't seem to be working now, I'm concerned something else may be wrong.
Wondering if anyone has seen the insulation melted off wires and how much heat do you need to get to that point???
There may be something wrong with your power supply, or the low voltage source. If there is, it should be at the unit itself, though I suppose a short of some kind could have occurred in the T-stat. I would post this question in HVAC, you may have some luck there.