Heat tune up Hoschton. Completed tune up on 2 16 year old systems. Both with good air flow and combustion. Changed both filters. Insulation and ductwork is good. Gas lines ran properly. Both have slightly dirty blower wheels and rusted evap coils. Both have worn flame sensors. Upstairs system has weak capacitor and inducer motor running at higher amps than rated for. Both systems missing secondary water safety device to protect furnace from water damage.