Which statement about sequence valves is true?

Which statement about sequence valves is true?

• A. Blocks all flow until the system is off
• B. Hold back flow until a set pressure is reached
• C. Diverts flow to tank
• D. Lowers system pressure

Answer: (B)

Sequence valves control the order of operation in a hydraulic circuit by holding back flow until the upstream pressure reaches a preset value. They stay closed as pressure builds, preventing flow to the next stage, and only open when the set pressure is reached. This timing ensures the first action completes or reaches the right load before the next actuator moves. That’s why holding back flow until a set pressure is the true statement: the valve’s purpose is to delay downstream flow until the required pressure is reached, enabling proper sequencing. It doesn’t block all flow until the system is off, it doesn’t divert flow to a tank, and it doesn’t purposefully lower the overall system pressure.

Sequence valves control the order of operation in a hydraulic circuit by holding back flow until the upstream pressure reaches a preset value. They stay closed as pressure builds, preventing flow to the next stage, and only open when the set pressure is reached. This timing ensures the first action completes or reaches the right load before the next actuator moves.

That’s why holding back flow until a set pressure is the true statement: the valve’s purpose is to delay downstream flow until the required pressure is reached, enabling proper sequencing. It doesn’t block all flow until the system is off, it doesn’t divert flow to a tank, and it doesn’t purposefully lower the overall system pressure.