What is a relay pump operation?

• A. A single pump trying to boost pressure.
• B. Pumps used only for drainage.
• C. A device that deletes water.
• D. A technique using multiple pumps in sequence to relay water from a source to a distant attack line when the source cannot provide enough pressure or volume.

Answer: (D)

Relay pump operation means using several pumps in sequence to move water from a source to a distant attack line when the source can’t provide enough pressure or volume on its own. The first pump draws from the water source and discharges into a supply line that feeds the next pump, which boosts the water pressure (and sometimes flow) again, and so on until the final pump delivers water to the nozzle with adequate pressure. This setup overcomes long distances, elevation changes, and friction losses that a single pump can’t handle. Proper relay pumping requires coordinating discharge pressures, priming each pump, and using appropriate hose sizes so each stage reinforces the next without creating backflow or weak points.