Performed a complete heating system maintenance and inspection. communicating 2023 Gas system. Inspected and tested all electrical components and safety controls on the indoor unit; all components tested within manufacturer specifications. Verified system temperatures: return air temperature measured at 71°F; supply air temperature measured at 107°F and rising. Confirmed air filter was recently replaced by client; filter size is 16” x 25” x 4”. And 20x25x4 Aprilaire I visually inspected the outdoor unit, The outdoor unit was in good condition Confirmed system was operating properly and heating upon departure. System Status: Operating normally at time of service.