Technical Parameters Parameter Specification Model Fisher 656 (Non-Relieving), 656R (Relieving) Type High-Pressure, Piston-Actuated, Pressure-Reducing Regulator Function Non-Relieving (656) or Relieving (656R) Connections (NPT) 1/4 in., 3/8 in., 1/2 in. Body Materials Forged Carbon Steel (Standard), Stainless Steel Internal Parts Stainless Steel, Buna-N (standard) Maximum Inlet Pressure 6000 psig (414 bar) Outlet Pressure Range Spring Ranges available, e.g., 5-50 psig (0.3-3.4 bar), 20-100 psig (1.4-6.9 bar), 50-250 psig (3.4-17.2 bar), and many other high-range springs. Temperature Limits -40°F to 200°F (-40°C to 93°C) with standard Buna-N elastomers. Flow Capacity (Cv) Approximately 1.8 (for a 1/2" NPT size). (Note: The 656 is designed for high ΔP, giving it a very high flow capability despite a Cv similar to smaller regulators). Leakage ANSI Class IV shut-off (bubble-tight). Mounting Panel mount (bracket required) or in-line.
