Surburban Furnace Fan Possessed!

[Taylormade]

I went to visit my 'stream at our storage lot a few weeks back and was surprised to find the furnace fan blowing when I opened the door. I've cut the thermostat off at the wall so there's no chance it's being "told" to come on by anything there.

After a few minutes of having the door and windows opened, the blower turned off.

I went back yesterday to take some measurements and found both new deep cycle batteries to be completely drained.

Does anyone know why my fan is coming on in the middle of summer?

[idroba]

That is really unusual, but about the only thing I can think of is that the furnace fan switch that holds the fan motor on when the burner is off (to cool down the furnace when the thermostat is satisfied) is defective and operating at a low enough temp so that the heat inside the trailer has it activated. This internal klixon switch operates independently of the wall thermostat settings, even the "off".

You say you "cut the thermostat off at the wall". Do you mean actually removed it, or just shut it off with the off switch at the thermostat itself? I suppose there is a possibility that the switch in the thermostat itself is defective, but that would only make the fan come on if it were cool in the trailer, not warm.

[Taylormade]

Originally Posted by idroba

You say you "cut the thermostat off at the wall". Do you mean actually removed it, or just shut it off with the off switch at the thermostat itself? I suppose there is a possibility that the switch in the thermostat itself is defective, but that would only make the fan come on if it were cool in the trailer, not warm.

Thanks for the feedback! I mean I literally cut the wires off and there's no thermostat on it right now. For the record, it was in the off position before I cut the wires as well.