The R312 Series second-stage regulators are designed for propane gas regulator systems and are listed by Underwriter’s Laboratories. The compact design of the R312 Series allows the unit to be installed in convenient outdoor locations and is less noticeable against the building on Two-Stage systems.

Standard vent orientation on the R312 Series is over the inlet; other vent positions are available. Materials are designed to resist corrosive environments and the molded fabric-reinforced diaphragm improves performance.

The spring case is color-coded green to easily identify the unit as a Second-Stage regulator.

The R422 Series regulators, like all second-stage regulators, reduce the pressure from a first-stage unit to 11-inches w.c. (27 mbar) in domestic installations. This unit is a high capacity regulator for commercial, industrial, and large domestic installations and comes with a large 1-inch FNPT drip-lip style vent.

Overpressure protection is provided by an internal relief valve and a travel stop on the closing cap. The R422 Series is compliant with NFPA 58 requirements.

The R522 Series Second-Stage regulators are compact, at 6.1-inches (155 mm), and are designed to serve typical domestic installations. Exclusive to Fisher products, the R522 Series is constructed of corrosion-resistant and wear-resistant materials. Easy system checks can be made on these units which have built-in gauge taps on both the upstream and downstream sides.

The regulators in this series are equipped for overpressure protection with an internal relief valve and a travel stop on the closing cap. The R522 Series is compliant with NFPA 58 requirements.

The R552 Series second-stage regulators reduce the outlet pressure from a First-Stage regulator, usually 10 psig (0,69 bar), to burner pressure, usually 11-inches w.c. (27 mbar). These regulators are designed for back mount installations, and feature the latest in regulator technology.

Like the R522 Series, the R552 Series is corrosion-resistant and has built-in 1/8-inch taps orificed to a Number 54 drill size on both the upstream and downstream sides to allow for easy gas system checks.