Arrived to HVAC maintenance for two full units. I began my maintenance on the indoor units. I first went over a few issues the home inspector went over with customer including air leaks around the suction line into the evaporator cabinet and an air leak from the condensation drain into the upstairs evaporator cabinet. I used thum gum to seal both of these. He then had concerns about rust build up in one of the return boots. This I attempted to clean this but it has become part of the duct. This will not effect the performance of the system unless the rust loosens or worsens. Upon performing maintenance of the upstairs unit I found the fuse on the board to be tripping continuously with 3amp fuses scattered throughout. This was due to a failing transformer. I also found the capacitor on the blower to have failed and the blower wheel to have substantial debris build up. Also with the heat exchanger having pitting and rust throughout I spoke to the customer about the age of the unit and is