I recently changed out my thermostat to a programmable one. It works fine at whatever temp it's set, but it doesn't run the program. I figured it was a problem with the thermostat and went and bought a different model. It's a simple two-wire (heat-only) configuration and I put the appropriate wires in Rh and W. With the new (2nd) thermostat, the heater turns on and doesn't shut off at all. It's not just the blower--it's emitting heat. Any thoughts?