Which component in the lateral control pit automatically cuts off the defuel pump when a predetermined amount of inches of mercury is reached?

The vacuum control switch operates by monitoring the pressure within the lateral control pit. When the pressure reaches a specific, predetermined level measured in inches of mercury, the vacuum control switch activates a mechanism that automatically shuts off the defuel pump. This functionality is crucial for preventing over-defueling and ensuring that the system operates within safe pressure limits, thereby protecting the equipment and maintaining operational integrity.

The vacuum control switch's role in this context makes it essential for automated safety in fuel management systems, as it helps avoid potential issues that could arise from excess fuel going into the system, such as contamination or operational malfunctions. Its automatic cut-off feature is key to maintaining safe and efficient operations within water and fuel systems.

Other components, such as the panel selector switch, the pump circuit breaker, and the solenoid control switch, serve different functions, such as user control options, circuit protection, and electrical switching, respectively. Their design does not provide the automated pressure monitoring and response function that is distinctive to the vacuum control switch.