Pumping systems — function of a foot valve on the suction line Foot valves fitted to pump suctions serve what basic valve function in the flow circuit?

Introduction / Context:
Foot valves are installed at the end of suction lines (often with a strainer) to maintain pump priming. Recognizing the functional class of this device helps in troubleshooting loss of prime and backflow problems.

Given Data / Assumptions:

• Foot valve sits at the suction inlet, typically submerged.
• It allows upward flow into the line but blocks reverse flow out of the line.
• No active actuation; it is a check-type device.

Concept / Approach:
A foot valve is essentially a check (non-return) valve. In valve-function taxonomy, any device that enforces one-way flow provides directional control. It prevents drain-back of liquid from the suction line and preserves prime when the pump is stopped.

Step-by-Step Solution:
Identify one-way function → non-return action.Map non-return to directional control category.Therefore, the best match among the options is “directional control.”

Verification / Alternative check:
Common pump manuals specify “foot valve (check valve with strainer)” for suction lift applications.

Why Other Options Are Wrong:

• Relief: limits pressure; not its role.
• Three/four way: used for flow routing in circuits; not applicable.
• Pressure reducing: maintains downstream pressure; not applicable.

Common Pitfalls:

• Confusing specific valve names with function classes. The functional category here is one-way (directional) control.

Final Answer:
directional control