The Pressure Sustaining Valve (Singer Model 106-RPS / 206-RPS) is a hydraulically operated, diaphragm-actuated control valve based on the 106-PG / 206-PG main valve. Its 81-RP pilot senses upstream pressure and modulates the valve to maintain a minimum pre-set inlet pressure, sustaining supply to higher-priority zones or pumps before allowing flow to continue downstream.

Features & Specifications

• Maintains a constant, adjustable minimum upstream pressure regardless of downstream demand

• Full-port (106) or reduced-port (206) globe or angle main valve

• Model 81-RP pilot with selectable spring ranges from 0.35 to 20.7 bar (5–300 psi)

• ANSI Class 150 / 300 flanges; drilled to ISO PN10 / PN16 / PN25 / PN40

• Sizes DN50–DN315; pressure classes PN16–PN40

• Pilot-system materials: ASTM B62 bronze / B16 brass, AISI 303/316 stainless-steel trim

• Buna-N / EPDM diaphragm and seals

• Adjustable closing-speed control for smooth, surge-free operation

• UL / FM designation available (specify 106-RPS-8700A)

Dimensions & Technical Data

Pilot-system schematic and component arrangement (Schematic A-0423F): 1) Main valve 106-PG/206-PG, 2/3/7/8) isolation valves & strainer, 4) fixed restriction 1/8 in / 3.2 mm, 5) Model 852-B closing speed control, 6) Model 81-RP pilot.