Watts M61115-74 - Manual

X – Isolation Cocks ○
FC – Flo-Clean Strainer ○
Y – Y-Strainer (Replaces Flo-Clean) ○
ACS – Adjustable Closing Speed ○
(Replaces Fixed Orifice)
AOS – Adjustable Opening Speed ○
P – Position Indicator ○
L – Limit Switch ○
8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.watts.com
06/08
M
ustang
s
eries
Standard Components
Options & Accessories
(3)
(3)
(3)
(2)
(2)
(1)
(1)
Standard 3” & Smaller
Standard 4” & Larger
Optional All Sizes (3)
(2)
(1)
Schematic
910 link
Throttles to reduce high upstream pressure to •
constant lower downstream pressure
Low Flow By-Pass controls at low flows •
Main Line valve controls at high flows •
Reducing and Low Flow By-Pass setpoints are •
separately adjustable
1
X
X X
Y/FC
(AOS)
P/L
2
3
4
CLOSES VALVE
OPENS VALVE
FLOW
M6115-74 (Globe)
M61115-74 (Angle)
1 – Main Valve (Single Chamber)
2 – Pressure Reducing Control
3 – Fixed Orifice
4 – Low Flow By-Pass
PRESSURE REDUCING VALVE
with
LOW-FLOW BY-PASS FEATURE
Operations
The Watts ACV Pressure Reducing Control Valve with Low Flow By-Pass is designed to automatically reduce a
fluctuating higher upstream pressure to a constant lower downstream pressure regardless of varying flow rates. It
is controlled by a normally open, pressure reducing pilot designed to: 1) Open (allowing fluid out of the main valve
cover chamber) when downstream pressure is below the adjustable setpoint, and 2) Close (allowing fluid to fill the
main valve cover chamber) when downstream pressure is above the adjustable setpoint. A decrease in downstream
pressure causes the valve to modulate toward an open position, raising downstream pressure. An increase in
downstream pressure causes the valve to modulate toward a closed position, lowering downstream pressure.
A Low Flow By-Pass Valve is piped parallel to the Main Pressure Reducing Valve, and is set approximately 10 PSI
higher. The Low Flow By-Pass handles flow requirements below the range of the Main Pressure Reducing Valve.
During “off peak” demand conditions, the Low Flow By-Pass provides flow and pressure to the downstream zone.
As flow requirements increase beyond the capacity of the Low Flow By-Pass, downstream pressure falls below the
setpoint of the Main Pressure Reducing Valve allowing it to throttle toward open, supplementing flow and pressure.
As flow requirements decrease, downstream pressure rises above the setpoint of the Main Pressure Reducing Valve,
causing it to throttle toward closed, allowing the Low Flow By-Pass to resume command of flow and pressure.