Which type of devices are crucial for controlling hazards in steam and hot water boilers?

Automatic limiting devices are essential for ensuring safety in steam and hot water boilers. These devices are designed to monitor specific parameters such as pressure and temperature, automatically shutting down the boiler or activating safety measures when those parameters exceed safe thresholds. This proactive approach helps prevent potentially dangerous situations, including explosions or equipment failure, by automatically taking corrective action.

In contrast, manual switches require human intervention and may introduce the risk of human error, as they depend on the operator to take action in an emergency. Electronic timers could control the timing of operations but do not specifically monitor hazardous conditions like pressure or temperature. Pressure monitors, while important for providing information about the system's status, typically do not have the capability to automatically take preventative measures. Thus, automatic limiting devices are uniquely suited for controlling hazards in steam and hot water boilers, making them critical for safe operation.