Performed FAU tuneup on 6 year old Lennox unit. Cleaned return grates. Cleaned condensate drain P trap and flushed with water. Tested external static pressure and found it to be high. Filter is undated and I couldn’t find anything in our notes about when it was last replaced. Jim will be ordering his own since I did not have any on my van. Inspected blower compartment, blower wheel is clean and balanced. Inspected electrical connections. Cleaned flame sensor. Tested resistance of hot surface igniter. Temperature rise is within limits. Phenomenal Aire was mentioned to Jim to help alleviate symptoms from allergies however he would like one installed at this time. Upon departure system is operational.