Working Principles: - When the valve is closed, anticlockwise rotation of the hand wheel lifts the pilot plug (3.1) off the larger balancing plug (3). This allows the medium to pass through the plug and equalizes the pressure of the medium under the plug (3). After the pressures have been equalized within the values stated in the table, the valve can be opened by turning the valve further with normal manual force.
Balancing plugs are fully effective only in closed systems.
The pressure of the medium on either side of the plug cannot be equalized in plants served by pumps operating on their characteristic.
The pressures of the medium on either side of the plug cannot be equalized if the medium is discharged into "open air".