What is the function of a jockey pump in an NFPA 20 system?

• A. To vent air from the main suction line
• B. To maintain system pressure and minimize cycling of the main fire pump
• C. To provide backup power to the main pump
• D. To automatically start the main pump on high demand

Answer: (B)

In NFPA 20, a jockey pump exists to hold the system at its target pressure. It starts whenever pressure begins to drop due to small demand or minor leaks and quickly brings the pressure back up to the set level, so the large main fire pump doesn’t have to start and stop for every small fluctuation. This keeps the main pump from frequent cycling, reducing wear, energy use, and nuisance starts, while the main pump remains ready to take over if a significant demand or fire event occurs. It isn’t used to vent air, provide backup power, or automatically start the main pump during high demand—the main pump is controlled by its own pressure switches and will start when pressure falls below its own threshold.