When you complete this lesson, you will be able to describe how to perform the checks and monitoring necessary to maintain operation of fans and their components. • Identify the reasons for monitoring a fan’s current bearing temperature, bearing vibration, and lubrication • List four checks you should perform as part of airpreheater maintenance • Explain how leaks in the heat exchanger can affect fan performance • Describe operational maintenance procedures involving ignitor air fans, scanners, excess air, and the boiler • Discuss how to overcome the effects of abnormal conditions such as hunting, stalling, excess temperature, and vibration