Performed heating maintenance on 2 year old Lennox unit.<br> <br> Cleaned return grate. Replaced filter with new owner-supplied MERV 16 filter. Temperature rise is within limits. Inducer amp draw as well as total system amp draw is within limits. Checked all electrical connections. Cleaned flame sensor. Tested all safety switches. Tested resistance of hot surface igniter. Inspected blower compartment and found blower wheel to be clean and balanced. Surge protection device is still active. Was unable to test external static pressure due to space constraints. Inspected ductwork and found it to be in good condition.<br> <br> Denise mentioned the room upstairs at the end of the hallway receives too much heating air. Because of this I closed the damper for that room from 60% to 30% and checked the supply on 2nd stage. During the summer this will most likely need to be opened up to keep up with the heat load of this room.<br> <br> Prior to departure I ensured the furnace was ope