The 2000 psi isolation valve is fail safe open and remains open unless an isolation occurs. What happens when power is removed?

The 2000 psi isolation valve is fail safe open and remains open unless an isolation occurs. What happens when power is removed?

• A. It opens automatically
• B. It closes automatically
• C. It does not change state
• D. Manually must be overridden

Answer: (A)

When power is removed, the valve goes to its fail-safe position: open. This valve is designed so that loss of electrical power allows the spring mechanism to drive it to the open state, restoring hydraulic flow. Under normal operation it stays open unless an isolation command closes it, but without power there’s nothing actuating a close, so it opens automatically.

When power is removed, the valve goes to its fail-safe position: open. This valve is designed so that loss of electrical power allows the spring mechanism to drive it to the open state, restoring hydraulic flow. Under normal operation it stays open unless an isolation command closes it, but without power there’s nothing actuating a close, so it opens automatically.