When testing a differential pressure gauge, where is water pressure bled through?

The correct choice indicates that water pressure is bled through the pressure vacuum breaker assembly air inlet valve during testing of a differential pressure gauge. This is crucial because the air inlet valve is specifically designed to allow air to enter the system, which helps in creating the necessary conditions for accurate pressure readings within the assembly. By bleeding water pressure through this valve, the technician can effectively assess the function of the differential pressure gauge while ensuring that any backflow prevention device operates correctly.

Understanding the context of the system is important; the pressure vacuum breaker is designed to prevent backflow by creating an air gap. Bleeding water pressure here allows for testing the differential pressure in accordance with safety standards and protocols set in backflow prevention practices. It ensures that the readings you obtain are reflective of real operational conditions, thus validating the integrity of the backflow prevention assembly.

In contrast, the other options do not serve the purpose of properly testing the differential pressure gauge. The main water supply line is not a designated location for bleeding pressure in the context of gauge testing. The relief valve is primarily for releasing excess pressure, while the shut-off valve is used to isolate sections of the system rather than for pressure testing purposes. These components are integral to the overall system but do not apply to the