When can the relief valve on a fire pump be adjusted to the closed position?

• A. During the churn part of a fire pump test.
• B. When a flow meter is used to perform the fire pump test at 150%.
• C. When it is deemed necessary to achieve minimum pump rated characteristics.
• D. When test header is opened to start the fire pump test.

Answer: (C)

The main idea is that the relief valve controls a bypass path that can prevent the pump from developing its full rated discharge. To verify the pump meets its required performance, you need the pump to load properly and deliver its rated head and flow. Closing the relief valve is done only when it’s necessary to force the pump to develop those minimum rated characteristics, ensuring an accurate measurement of performance. It isn’t appropriate during the churn warm-up, a test conducted at 150% flow, or the start of the test header, because those steps don’t require removing the bypass to achieve the rated performance. Closing the relief valve in this targeted way ensures the pump is tested under the conditions that reveal its true capabilities.