Just finished seasonal maintenance on Trane XR16 system. Cleaned condenser coils (they were FILTHY!), checked refrigerant pressure (spot on), and replaced air filter. Inspected electrical connections and tightened several loose terminals on contactor. Cleaned condensate drain line with nitrogen blast - was partially clogged. Unit running at peak efficiency now, just in time for summer heat. Recommended duct cleaning next visit due to visible dust accumulation. Great folks, super friendly dog!