How should you manage air in the discharge line to prevent surging?

• A. Increase the air content to dampen surges.
• B. Ensure the line is fully primed and free of air pockets before charging to maintain stable flow.
• C. Purge the air after charging.
• D. Vent air only after full flow is established.

Answer: (B)

Air in the discharge line can cause surges because air compresses and creates abrupt pressure changes when water is pushed through the line. The way to prevent that is to have a continuous water column with no air pockets before you start charging the line, i.e., ensure the discharge line is fully primed and free of air pockets. When the line is water-filled from the start, the flow remains steady and you avoid the rapid pressure fluctuations that cause surging. Purging after charging or venting only after full flow is established is too late to stop the surge, and increasing air content would actually worsen the problem.