These heavy duty, pilot operated, iron alloy (ASTM A126 Class B) pressure regulators are suitable for R-717, R-22, R-502 and other common refrigerants and fluids approved for use in refrigeration systems. All/4 Regulators are pilot operated using upstream pressure for the opening force and require a minimum 2 psi (0./4 bar) pressure drop to fully open. These valves are generally ordered with a close coupled upstream strainer to prevent the entrance of foreign material into the valve and the rest of the system. The fluid temperature range for the/4 Series of Regulators is -50F to 220F (/45C to 105C).