AC/HEAT MAINTENANCE. Found system operational upon arrival. Replaced standard 20251 filter. The filter that was in there before the maintenance was past due and restrictive. Blower clean. Evaporator clean. Burners and burner cabinet clean. Gas pressure ok. Inducer ok. Limits and switches operational at this time. Board ok. Flame sensor ok. Igniter ok. Temp rise ok. Static ok. Washed condenser coil. Freon pressures ok. Temp split ok. Motor and compressor amps ok. Motor bearings ok. Motor control is within range at this time. High voltage line relay in good condition. Unit operational upon departure.