I recently bought a new digital Honeywell line-voltage thermostat to replace my current one. The thermostat controls one 240V wall heater. I'm having some trouble because the wiring is different on the new one compared to the old one (and Honeywell doesn't provide adequate directions for an idiot like me).
This is my current thermostat and wiring:
Although the photo doesn't show it, the red wire from the thermostat is wire-nutted to two black wires, the black wire from the thermostat is connected to another single black wire.
Okay, so here is my new thermostat:
A helpful person on Usenet gave me the following advice:
Unless the thermostat does something "intelligent" to monitor load, you
should be able to treat the new thermostat as a single pole switch, same
as your old one. This would switch only one side of your heater,
leaving the other hot all the time.
Take the single black wire connected to the black thermostat wire, and
hook it up to the inner black wire. Insulate the end of the outer black
wire--this will be live when the heat is on.
Split the two black wires hooked to the old red wire, connect the one
going to the heater with the outer red wire, and the one going to the
supply to the inner red wire.
I tried this, and the thermostat turns on fine, and "clicks" to show it's turning the heat on. The problem is that the heat doesn't come on. Does anyone have any other ideas I could try?