On my floor furnace, the pilot light will light and stay lit but the burner will heat and work properly for one day and would not work the next day. I jumped a wire across the two thermostat connectors on the gas valve and still could not get it to start the burner. It is a new gas valve. It has a low pilot light but does stay on and seems to be hot enough to work. I tried bypassing the limit switch, to use the thermostat alone and now it will not turn off. Could it be a bad limit switch? But then why won't it shut off with thermostat alone? :confused:

Pull off ALL your jumper wires!