Before operating a changeover valve, what should be done to the engine pressure?

The correct approach before operating a changeover valve involves reducing the engine pressure to a specific level, in this case, dropping it to 50 PSI. This procedure is essential because a changeover valve is utilized to switch water supply sources, typically from a tank supply to a pressurized water source or vice versa.

By reducing the engine pressure to 50 PSI, you prevent any potential damage or stress on the plumbing and equipment involved in the operation. High pressure can cause excessive force on the valve, leading to malfunctions or leaks during the transfer process. Furthermore, it ensures that any system changes made are smooth and controlled, reducing risks to personnel and equipment.

Maintaining the current engine pressure might not account for the increased stresses that could arise from switching sources under higher pressure. Increasing the engine pressure to 70 PSI, on the other hand, could exacerbate these issues. Shutting down the engine completely could interrupt necessary functions and hinder the ability to respond efficiently to a fire situation. Therefore, dropping the pressure to the recommended level is the most effective method to ensure safe and efficient valve operation.