Performed FAU maintenance on 1-2 year old York unit. Replaced merv 16 filter with owner-supplied filter. Cleaned condensate drain P trap and flushed with water. Inspected blower compartment, blower wheel is clean and balanced. Tested static pressure. Inspected electrical connections. Inspected flame sensor. Tested resistance of hot surface igniter. Temperature rise is within limits. Tested all safety and limit switches. Condenser cover installed, do not operate in cooling mode. Upon departure system is operational.