How should the pump head relate to system demand?

• A. The pump head must be less than system head.
• B. The pump head is irrelevant.
• C. The pump head must meet or exceed the system's required head to deliver the needed pressure.
• D. The pump head must be twice the system head.

Answer: (C)

The essential idea is matching what the system needs with what the pump can provide. The system demand is the pressure (head) required to push water to the most distant or critical points in the system, taking into account static head and friction losses along the piping. The pump head is the pressure rise the pump can deliver at a given flow. To ensure the required pressure is available, the pump head must meet or exceed the system’s required head at the design flow. When the pump and system curves align, the operating point sits at the intersection, giving the required pressure and the intended flow. If the pump head is less than what the system needs, the desired pressure won’t be reached; if it’s higher, you’ll still meet the demand, though efficiency and control considerations come into play. So, the pump head should meet or exceed the system’s required head to deliver the needed pressure.