Customer states second floor unit was not heating this morning or blowing any air at all. Thermostat showed heat on, but there was no heat. Upon arrival, customer informed me that he turned the furnace off and then back on, and the heat works now. This indicates the furnace was likely in some type of lockout. I was able to recall the previous three faults on the furnace. The last three faults from most recent to least were: -7 red flashes indicating’ failed to light burners’ -4 red flashes indicating’ airflow problem or open fuse’ -3 red flashes indicating’ vent or termination problem’ I observed operation throughout multiple power cycles. Tested gas valve, ignition, heat rise, and flame sensor. The burners appear clean with no impingement at the transfers more otherwise. Gas pressures are properly set at low and high stage. Flame sensor is reading 2.3 mA which is within healthy range. Heat rise on both low and high fire were between 22 and 35° which is very much on the lower end of