Arrived on site to perform diagnostic on a 1977 Day N Night system. Unit located in garage and original to home. As she stated she had home inspected and system would turn on and shortly after would shut off. Cycled system and system did fire up. Advised client we would do a safety evaluation due to system age and condition. Pulled blower assembly wheel is really dirty and shows water spots in blower. Motor has oil leaking and had dirt and oil accumulating. Inspected heat exchanger. Found system to show indefinite signs of age and self wear as each chambers had the inner metal walls deteriorating and crumbling up and build up was accumulating burners and could clogged them up over time. Cleaned off burners and hydro scanned system. Overall condition of system is in bad condition. Cycled system to ensure is operational. Over system maybe operating but not in a good condition or efficiently. Evaporator coil is dirty system only has on drain line and no safety Overflow switches. System is