Arrived on site to perform furnace diagnostic on Lenox heater. Upon arrival client said unit started working but still continued to do troubleshooting. Performed full diagnostic on unit, system checked out properly with no error codes. Reset unit three times and it heated with no issue. Filter with swapped out last maintenance. Flame sensor was cleaned off. Client signed up on maintenance plan to keep unit at standard. Activated dealer controls for remote access for future. Upon departure unit is operational and heating