When can you NOT use a valve wrench?

• A. When there is a gear box
• B. When the valve is fully open
• C. When the valve is being tested
• D. When the valve is hot

Answer: (A)

The key idea is that valve wrenches are only used on valves without a geared or automated operation. When a valve has a gear box, you should operate it through the gear mechanism (or the actuator) rather than with a separate wrench. Using a wrench on a stem when a gearbox exists can overwrite the designed control and torque provided by the gearbox, risking damage to the stem, packing, or gears, and it can lead to uncontrolled or jerky movement. So, you cannot or should not use a valve wrench when there is a gear box.