Performed heating maintenance to a 2005 Trane single stage 93% efficient gas furnace Pulled and cleaned flame sensor Pulled condensate trap and flushed with water 20x25x4 filter is good Replaced humidifier water panel (#35) and opened bypass damper Humidifier is operating properly, no water leaks and solenoid functioning correctly Concern of high water bill from humidifier can be due to extensive run time. Set humidistat to a lower setting. Run tested furnace Combustion numbers are good Gas pressure 3.5 Temp rise 45 Furnace began kicking out on pressure switch Found condensate elbow off the inducer plugged solid Cleared debris from that line Run tested furnace again No faults occurred again Furnace is operating within spec at this time