What controls the fuel flow direction in the HP pumping elements?

What controls the fuel flow direction in the HP pumping elements?

• A. Paralleling valve
• B. Check valve
• C. Flow divider
• D. Shut-off valve

Answer: (A)

The function is handled by the paralleling valve. In a dual high-pressure fuel system, this valve sits between the HP pumps and the fuel control and directs which pump’s output feeds the system. It uses pressure differences to open the path from the active pump and block the other, preventing backflow and cross-flow. When both pumps are operating, it allows both outputs to share the load; if one pump isn’t delivering, the valve isolates it and routes flow from the remaining pump to the engine. This active routing is what controls the fuel flow direction in the HP pumping elements.

The function is handled by the paralleling valve. In a dual high-pressure fuel system, this valve sits between the HP pumps and the fuel control and directs which pump’s output feeds the system. It uses pressure differences to open the path from the active pump and block the other, preventing backflow and cross-flow. When both pumps are operating, it allows both outputs to share the load; if one pump isn’t delivering, the valve isolates it and routes flow from the remaining pump to the engine. This active routing is what controls the fuel flow direction in the HP pumping elements.