Heat? '86 PT_40

[pauleburgess]

It looks like my under-sofa heat doesn't follow any of this. After a few hours of getting nothing, I pulled it out. As I was pulling it out, in the process shaking it, it came on... briefly. Opened it up, and quickly saw why it wasn't coming on. Black wire of 110V was melted, broken-- the wire nut that held it also melted. Shaking it around made it make contact with the other half of itself. With all HVAC related breakers off and switches over driver off--- I asked my wife to vacuum it out and wipe down some of the dust with a wet rag, while I got the electrical kit to figure out how to splice in new wire. For some reason, I reached in just before the wet rag showed up, and I got a nice tingle off that black wire. What? Breaker is off! Yet 110VAC still present. It seems that it is not an original wiring job, and is tied into the front receptacles breaker.

Lessons: Don't trust any breaker box labels. There's 30 years of rewiring here. Always probe with the multimeter.

No wires from thermostat come to the box, and I don't suspect the thermostat is running a relay for this one. The rheostat in the heater seems to turn it on/off and sets temperature pretty well.

Any idea about the power to the thermostat? is it 24VAC from a hidden transformer somewhere (where?)? I know I won't get any voltage by probing across the leads in the thermostat-- I've got to find connection to the common somewhere (can I use chassis ground for that?)

Next weekend -- bedroom and bathroom electric heat.