Heating system maintenance Dacula. Completed maintenance on 2 20 year old systems. Both system running as of now. Both blower wheels very dirty. Downstairs capacitor is weak and out of range. Needs to be replaced. Combustion is good upstairs. Pressures seem to be in range downstairs. Air flow is good on both systems. Neither system has back water safety device to protect furnace from water damage. Both evap coils very rusted and corroded. Both running on r22 Freon that has been phased out. Recommend replacing systems for better efficiency.