Upon arrival, client said fan motor would short cycle. Unit would heat up to 150 and the fan limit switch would energize the fan motor. The heater would heat between 148-150. Turning the fun on and off. Adjusted the setting to energize the fan at 130. The system is now heating properly. The system is older. Fan motor is in bad shape. Heat exchanger is deteriorating inside from age. It is highly recommended to replace the system for safety. Advised client of findings. Client is budgeting for replacement. Client signed up on maintenance plan. System is operational upon departure.