The 83-RP is a spring and diaphragm operated, normally closed pilot specifically designed for high pressure applications. The inner valve is held closed by the spring. When the control sensed pressure below the diaphragm exceeds the force of the spring, the pilot valve opens.
Model 83-RP pilot is used as the standard pressure relief pilot where the operating pressures are excessive, such as a 300 psi / 20.7 bar level.
For more information on the 83-RP: