What component opens the electrical control circuit when the defuel pump shuts off?

The component that opens the electrical control circuit when the defuel pump shuts off is the vacuum control switch. This switch is designed to respond to changes in pressure, specifically recognizing when the suction created by the pump drops below a certain threshold, indicating that the pump has ceased operation. When such conditions are met, the vacuum control switch will open the circuit to prevent the electrical system from continuing to energize the defuel pump unnecessarily.

This mechanism serves as an essential safety feature, ensuring that the system remains controlled and that there are no unintended operations of the pump when it is not needed. Understanding the role of the vacuum control switch emphasizes the importance of pressure monitoring in fluid systems, which ensures safe and efficient operation while preventing potential equipment damage or hazardous conditions.

Other components like the pump circuit breaker, pump control switch, and air control switch have distinct functions within the system but do not directly serve the purpose of disconnecting the electrical control circuit specifically in response to the defuel pump shutting off.