Which role does a jockey pump play in a fire pump system?

• A. Stores excess fuel.
• B. Purges air from discharge lines.
• C. Provides emergency power to the main pump.
• D. Maintains system pressure and reduces cycling of the main pump.

Answer: (D)

The jockey pump’s job is to hold the system at a stable pressure so the large fire pump doesn’t cycle on and off with every small demand. It automatically starts when system pressure falls below a set point and stops when pressure nears the set point, keeping the discharge lines and risers pressurized and reducing the number of starts and stops of the main pump. This minimizes wear, energy use, and shortens pump life cycles while ensuring the system is ready to deliver water quickly if a real demand occurs.

It doesn’t store fuel, purges air from discharge lines, or provide emergency power to the main pump. Fuel storage and emergency power are separate concerns for the main pump, and purging air is handled by other components in the system (such as air release valves and priming methods).