This publication provides an introduction to instruments and devices employed in boiler control systems. Both panel instruments and local devices and instruments are discussed. Requirements are provided for controllers, recorders, totalizers, indicators, status lights, annunciators, selector switches, pushbuttons, and plant control stations. You will learn about control valves, pressure regulators, solenoid valves, actuators, current-to-pneumatic converters, dampers, pressure relief valves, rupture disks, level instruments, flow instruments, temperature measurements, pressure measurements, electronic transmitters, electrical instrument switches, analyzers, flame detectors and continuous emission monitoring. You will be introduced to recommended boiler control panel instrumentation as well as local boiler devices.