Which component's malfunction would prevent the AFFF service flow?

• A. CO2 actuator
• B. Powertrol valve
• C. T valve
• D. SOPV

Answer: (B)

In an AFFF system, the path that delivers foam to the discharge is controlled by a power-trol valve. This valve meters and routes the pump output into the foam system, directing the foam solution to the discharge manifolds. If the power-trol valve cannot move or seal properly, there is no way to allow the foam solution to reach the discharge lines, so service flow is blocked. The CO2 actuator is only the mechanism that moves the valve; if it fails, the valve may not operate, but the fundamental issue is that the valve itself cannot regulate flow to the AFFF path. The T valve is a branching/diverter and, if stuck, could alter flow paths but isn’t the primary controller of service flow. SOPV controls pressure or sequencing in parts of the system, but without a functioning power-trol valve, the AFFF service flow cannot be established.