Furnace not working? Just bought my first house, and the indian summer is over, time for the heat. I don't have the first clue how to turn the furnace on. Went into the utility room, the power switch was turned up/on, checked the filter and its a little dirty but shouldnt affect operation, took the cover off the furnace and the gas valve was in the "on" position. Did a bit of googling, turned the power switch off for five minutes, then back on, and did the same with the gas valve, and nothing. There is a simple thermostat that controls the temp, and the AC works fine but the furnace does nothing at night when the temp falls well below the thermostat setting. Checked the circuit breaker and that's good. ???