My old thermostat. . .

Probably worth putting a volt meter across those two wires to see what they’re reading, but thermostat controls are usually really simple: Connect the wires, the furnace turns on, disconnect ‘em, it turns off.

-- Dan Lyke, Petaluma California, http://www.flutterby.net/

I have a new electric thermostat, and it has 7 possible coded inputs. Therein lies the problem.

I take it that you only have a heater hooked to the thermostat. The new electronic thermostats will control you heat, air, ventilation fans and coffee pot. Like Dan said connect them, it goes on, disconnect, off. If you look at the instructions for your thermostat, it should tell you which one to connect for just the heat. Usually these wires will just be completing the circuit to a relay, which does the rest.

-- Tim - http://www.tmuli.com

On your new thermostat and its 7 connections, I’m not sure how those things are set up these days, but if one is “ground” then use a volt meter in “DC” mode to see if one of the wires you’ve got is positive and one is negative. Plug the negative one into the “ground” pin. If you don’t get a solid reading off the wires, the furnace is putting out AC on those wires and you’re on your own.

-- Dan Lyke, Petaluma California, http://www.flutterby.net/