Performed heating maintenance on a Trane 96% efficient two stage natural gas furnace Filter new Humidifier water panel good for this heating season... opened water supply valve and run tested, no leaks. Opened bypass damper and set humidity to level 5 on the automatic controller Pulled and cleaned flame sensor Blew out Condensate trap Ran combustion test. Readings within nominal range. No carbon monoxide present in supply or return air Gas 3.5 for high fire and 1.9 for low fire Temperature rise within specification range for both fire rates while the bypass damper for thr humidifier is open. Furnace operating within manufacturer's specifications at this time.