McDonnell and Miller Series 250 Pressure Relief Valve

McDonell & Miller diaphragm operated cast iron and diaphragm-assist operated bronze ASME Safety Relief Valves are designed to protect fired and unfired hot water pressure vessels against over-pressure conditions. The diaphragm's "oversizes" effective area generates a greater operating force which helps to overcome the effects of fouling. These valves feature a unique fail-safe disc with sufficient area to permit the valves to maintain their safety relief fundtion, in the even of a diaphragm rupture.  These valves are designed, manufacture, tested and labeled in accordance with the requirements of Section IV of he ASME Boiler and Pressure Vessel Code.  They are offered in a wide range of capacities to permit a close match with the boiler output rating.

Features:

• For tanks and hydronic heating systems
• Protects against over-pressure
• Minimizes hammering with flash steam
• Low differential pressure – 3 psi (.21 kg/cm2) between opening and closing
• Meets ASME Pressure Vessel and Boiler Code, Section IV
• Sizes and material
  • – 3⁄4" - 1" NPT – bronze body and seat
  • 2" NPT – cast iron body, brass seat
• EPDM rubber diaphragm and seat disc
• Maximum temperature 250°F (121°C)
• Maximum operating pressure range 30 - 125 psig (2.1 - 8.8 kg/cm2)