Servicing control valve shall not be opened more than how many turns?

• A. 1/2 turn
• B. 3/4 turn
• C. 1 turn
• D. 2 turns

Answer: (B)

Opening the servicing control valve only up to three-quarters of a turn is about staying within safe motion that the valve is designed for during servicing. This small movement is enough to accomplish the intended service action (such as venting or priming) without exceeding the limits of the valve stem, packing, and seating. If you go beyond that limit, you risk damaging the valve components, causing leaks, or disturbing the valve’s calibration, which can affect system performance later. A smaller amount (half turn) may not provide the needed access for servicing, while turning more than three-quarters increases the chance of damage or unintended flow.