First-Stage regulators reduce tank pressure to a lower pressure (usually 10 psig or 0,69 bar) for a Second-Stage regulator. Fisher First-Stage regulators are painted red for easy identification. Vents are screened with standard orientation over the outlet.

Type R312H Designed for use as the First-Stage portion of a Two-Stage regulation system on domestic applications. With an overall length of only 4.13(105 mm) and flush mounting boss, the R312H fits easily under the tank dome. Designed as non-adjustable, the unit is virtually tamper proof. Outlet pressure remains at the factory nominal setting of 10 psig (0,69 bar). Each unit contains a relief valve and a large vent. Fishers exclusive fabric-reinforced diaphragm and cast orifice provide accurate regulation. The spring case is color-coded red to easily identify the unit as a First-Stage regulator. A P212 vent tube extension is available for underground installations. A P213 90; vent adaptor is available for horizontally installed regulators. For ordering information see page 21.

Type R522H Constructed of corrosion-resistant and wear- resistant materials, the R522H is less susceptible to corrosive environments. Built-in 1/8 FNPT gauge taps on both the inlet and outlet pressure sides allow for easy system checks. A large 3/4 FNPT drip-lip vent reduces the chance of blockage by freezing rain or sleet when properly installed with the vent pointing down.

Each R522H is equipped for overpressure protection with a corrosion-resistant internal relief valve that provides high capacity relief and a travel stop on the closing cap. Its overall profile of 6.13(156 mm) makes it ideal for under the dome installations.