In what operational mode should pressure governors be set while functioning as a relay pumper?

When operating as a relay pumper, pressure governors should be set to RPM mode. This mode is designed to maintain the engine speed at a set RPM rather than adjusting to maintain a specific pressure. By using RPM mode, the relay pumper can ensure that the pump operates at the necessary flow rates without artificially limiting pressure, which is crucial in a relay operation where multiple pumpers are working together to supply water to a fire scene over longer distances.

In this scenario, it is important for the pumper to maximize available engine power and flow capabilities, especially since it is receiving water from another pumper and may be tasked with pushing water through longer lines or at higher elevations. RPM mode helps in achieving optimal performance under these circumstances by keeping the engine running efficiently, ensuring that water delivery remains consistent and reliable.