Came out to perform preventative maintenance on 2 furnaces for customer. Discussed with customer about filters, how the units have been doing and just about life in general. Customer will take care of filters. I started by inspecting the ductwork, blower assemblies, electrical components, heat exchangers, burners, flame sensors, ignitors, gas valves, inducer motors and overall condition of all equipment. Cleaned flame sensors and brushed dust off the burners and components. Checked operation, wiring, capacitors, amps, temperature rise and gas pressure of furnaces. Trane furnace has no signs of failures at this time. Inducer motor is close to max amp reading. Customer is aware the system is aging and that it will eventually need replacement. Systems are heating properly within manufactured specifications at this time.