What action must be taken when a gate valve shows signs of wire drawing?

When a gate valve shows signs of wire drawing, this indicates that the valve seating surfaces have been damaged due to prolonged usage or improper operation. Wire drawing occurs when the valve's surface is subjected to excessive flow conditions, leading to erosion and a rougher surface. In this condition, the valve can no longer provide a proper seal, which is crucial for controlling the flow of fluid effectively.

Replacing the gate valve is essential because attempting to clean, lubricate, or repair a valve with significant wear like wire drawing would not restore its functionality or sealing capacity. The valve's effectiveness and reliability depend on the integrity of its seat surfaces, and if those are compromised, the valve will not perform as required in the system. Therefore, replacing the valve ensures that the plumbing system continues to operate efficiently and safely.