Opening or closing the main pump drain under pressure can cause what outcome?

Opening or closing the main pump drain under pressure can cause what outcome?

• A. Damage will occur and the valve will not close
• B. The valve will close properly
• C. No effect
• D. It will relieve pressure safely

Answer: (A)

Opening or closing the main pump drain while the system is under pressure creates a sudden pressure change that can produce water hammer. That shock can damage the valve seat, stem packing, and nearby piping, and debris or deformation from the surge can cause the valve to fail to seal properly. So, the drain may cause damage and the valve may not close afterward. The safe practice is to depressurize the system before operating the drain and perform any drain operations slowly after relieving pressure.

Opening or closing the main pump drain while the system is under pressure creates a sudden pressure change that can produce water hammer. That shock can damage the valve seat, stem packing, and nearby piping, and debris or deformation from the surge can cause the valve to fail to seal properly. So, the drain may cause damage and the valve may not close afterward. The safe practice is to depressurize the system before operating the drain and perform any drain operations slowly after relieving pressure.