What device prevents the pump from inducing too low of a negative pressure when the vacuum switch fails?

A vacuum breaker is a device designed to prevent the development of a negative pressure that could lead to issues such as backflow or collapse of the system being used to create suction. When a pump operates, it can create a negative pressure, and if this pressure gets too low—especially in the event of a fail-scenario for the vacuum switch—a vacuum breaker will activate to allow air into the system. This prevents the pump or piping system from experiencing excessive vacuum conditions that could cause physical damage or operational issues.

In essence, the vacuum breaker plays a crucial role in maintaining safe operational pressures within the system, ensuring that it does not fall into potentially harmful negative pressures under any circumstances. This makes it the appropriate choice for the question regarding the protection of the pump from inducing too low a negative pressure due to a vacuum switch failure.