Performed heating maintenance Trane S9V2 two stage 96% efficient gas furnace Gas pressure 3.5 for high and 1.7 for low fire rates 35 degree temperature rise for low fire and 41 degrees for high fire Condensate trap clear Changed aprilaire 210 filter Replaced aprilaire 35 water panel Blower is clean York 2 stage 96% efficient gas furnace Pulled and cleaned flame sensor High fire gas pressure 3.5 combustion test pass Temp rise 32 degrees Low fire gas pressure 1.9 combustion test pass 30 degree temp rise Trap clear Filter good Blower clean Lennox single stage 80% efficient furnace Pulled and cleaned flame sensor Replaced filter Gas pressure 3.7 Temp rise 40 degrees Blower clean Cleared pressure switch port on the inducer housing. Flue pipe is rusted out and needs replaced.