Watts M1115-74 - Manual (Page 7)

8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com
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Specifications
M115-74 (Globe)
M1115-74 (Angle)
The Pressure Reducing Control Valve with Low Flow By-Pass shall be a pilot operated diaphragm valve
designed to automatically reduce a fluctuating higher upstream pressure to a constant lower downstream
pressure regardless of varying flow rates. Flow requirements below the normal range of the main line
Pressure Reducing Control Valve shall be handled by a valve mounted, direct acting, Low Flow By-Pass
valve.
The main valve shall be a hydraulically operated, single diaphragm actuated, globe or angle pattern valve.
Y-pattern valves shall not be permitted. The valve shall contain a disc and diaphragm assembly that forms
a sealed chamber below the valve cover, separating operating pressure from line pressure. The diaphragm
shall be constructed of nylon reinforced Buna-N, and shall not seal directly against the valve seat and shall
be fully supported by the valve body and cover. Rolling diaphragm construction will not be allowed and there
shall be no pistons operating the main valve or any pilot controls.
The main valve body and cover shall be Ductile Iron ASTM A536, and all internal cast components shall
be Ductile Iron or CF8M (316) Stainless Steel. All Ductile Iron components, including the body and cover,
shall be lined and coated with an NSF 61 Certified Epoxy Coating applied by the electrostatic heat fusion
process. All main valve trim and throttling components (cover bearing, valve seat and disc guide) shall
be Stainless Steel. The valve body and cover must be machined with a 360-degree locating lip to assure
proper alignment.
The disc and diaphragm assembly shall contain a Buna-N synthetic rubber disc with a rectangular cross-
section that is securely retained on 3-1/2 sides by a disc retainer and disc guide. Diaphragm assemblies
utilizing bolts or cap screws for component retention will not be permitted.
The exposed portion of the seat disc shall contact the valve seat and seal drip-tight. The disc and diaphragm
assembly must be guided by two separate bearings, one installed in the valve cover and one concentrically
located within the valve seat, to avoid deflection and assure positive disc-to-seat contact. Center guided
valves will not be permitted. All necessary repairs shall be made from the top of the valve while the body
remains in line.
Pilot control systems for valves 3” and smaller shall contain a Flow Clean Strainer, Fixed Orifice Closing
Speed, Adjustable Opening Speed Control, Low Flow By-Pass and Pressure Reducing Pilot. Pilot control
systems for valves 4” and larger shall contain an external Y-Strainer, Fixed Orifice Closing Speed, Low
Flow By-Pass and Pressure Reducing Pilot. All pilot control systems shall utilize copper tubing and brass
fittings and must be equipped with Isolation Ball Valves on all body connections regardless of valve size.
The adjustment range of the Low Flow By-Pass shall be 20-200 psi and the pressure reducing pilot shall
be 30-300 psi.
The valve shall be Watts ACV Model M115-74 (Globe) or M1115-74 (Angle) pattern Pressure Reducing
Control Valve with Low Flow By-Pass.
Other Watts ACV Pressure Reducing Control Valves
M115 / M1115 Pressure Reducing Valve
M115-3 / M1115-3 Pressure Reducing Valve with Hydraulic Check Feature
M115-7 / M1115-7 Pressure Reducing Valve with Surge Control Feature
910 Ops & Inst