What are the two types of fuel valves?

• A. Check and Control Valves
• B. Needle and Globe Valves
• C. Ball and Gate Valves
• D. Pressure and Temperature Valves

Answer: (A)

In fuel systems, two fundamental valve functions are to prevent backflow and to regulate fuel delivery. The best answer reflects these roles: check valves and control valves.

A check valve lets fuel flow in only one direction. This prevents reverse flow or siphoning when pumps shut down or pressures shift, protecting pumps and tanks.

A control valve actively modulates how much fuel passes through, to meet engine or system requirements. It acts like a throttle, opening more or less to maintain the desired flow and pressure.

The other options describe valve types that can exist in systems, but they aren’t the standard pair described as the two main fuel valves. Needle and globe valves are throttling/flow-control valves, ball and gate valves are general shut-off types, and pressure/temperature valves refer to relief or sensor-related functions rather than two basic fuel-valve types.