The underground main may be flushed after connection is made to overhead sprinkler piping.

The underground main may be flushed after connection is made to overhead sprinkler piping.

• A. No, flushing is not required
• B. Yes, to remove debris
• C. Only if pressure drops
• D. Only during testing

Answer: (B)

Flushing the underground main after it’s connected to the overhead sprinkler piping is done to purge debris that can enter the line during excavation and installation. The underground main can carry dirt, rust, or other particles that, if not removed, may travel into the overhead piping and clog or impede sprinkler heads, valves, or orifices. By purging the line through drains or test valves until clear water flows, you protect system performance and ensure accurate startup and testing results. This is a standard step in start-up to keep the system clean, not something you do only if a pressure drops or only during testing.

Flushing the underground main after it’s connected to the overhead sprinkler piping is done to purge debris that can enter the line during excavation and installation. The underground main can carry dirt, rust, or other particles that, if not removed, may travel into the overhead piping and clog or impede sprinkler heads, valves, or orifices. By purging the line through drains or test valves until clear water flows, you protect system performance and ensure accurate startup and testing results. This is a standard step in start-up to keep the system clean, not something you do only if a pressure drops or only during testing.