What is the importance of closing the discharge valves one at a time during the pressure control test?

Closing the discharge valves one at a time during the pressure control test is crucial for ensuring accurate pressure readings. This method allows the operator to monitor the effect each valve closure has on the system's overall pressure. If multiple valves were closed simultaneously, it would create uncertainty regarding which valve's closure contributed to any observed changes in pressure. By carefully managing the closure of each valve, operators can obtain precise and reliable data, which is essential for evaluating the system’s performance and making necessary adjustments. This practice directly influences the effectiveness of the pressure control test and supports safe operation of the mobile water supply system.