Performed preventative maintenance on heat pump system with gas emergency heat. I started with the gas furnace. Replaced customer supplied media filter. Inspected the blower assembly, motor, capacitor, electrical components, burners, flame sensor, ignitor, gas valve, inducer motor and overall condition of equipment. Cleaned flame sensor and brushed dust off the burners and components. Checked amps, temperature rise and gas pressure of furnace. Adjusted gas pressure to unit requirements. Checked over heat pump system. Inspected control board, contactor, capacitor and condition of the other components. Cycled system on and checked amps, temperatures and pressures. Heat pump is getting older and is operating off of R-22, but still operating properly within manufactured specifications.