The driver should select the mode when pumping approximately what percent or more of capacity?

• A. 60%
• B. 70%
• C. 50%
• D. 80%

Answer: (B)

Two pump control modes exist to match how you want to manage flow and pressure. One mode focuses on delivering a chosen flow, while the other focuses on maintaining a chosen discharge pressure, adjusting flow as needed to hold that pressure.

When you’re pumping a substantial portion of the pump’s capacity, switching to the pressure-control mode helps keep the nozzle pressure steady as demand and hose losses change. About seventy percent of capacity is the point where stability becomes more critical, so moving into pressure mode at that threshold helps prevent pressure swings and keeps the operation safer and more predictable.

Lower flow levels (well under this threshold) don’t usually require switching because the demand is easier to manage in volume mode. Waiting until much higher flow (around eighty percent or more) can mean you miss the opportunity to stabilize pressure as soon as it’s needed, so seventy percent is the practical guideline.