Position indicator and auxiliary contacts in gas train solenoid valves

Many gas train valves are equipped with auxiliary contacts or a position indicator so that the control system knows whether the valve is open or closed.

Position indicator

It provides a visual or electrical indication of the actual position of the valve mechanism.

Auxiliary contacts

Auxiliary contacts can be used for permissives, interlocks, alarms, or sequence confirmation.

NO and NC contacts

It must be clear which contact is being used and which state the system considers safe.

Common problem

Incorrect adjustment or mechanical loosening of the switch may provide false feedback even though the valve is operating normally.