Standard Components
Operation
The Rate-of-Flow ACV with Pressure Reducing Feature is designed
to automatically limit flow rate to a constant, adjustable, maximum,
and reduce a fluctuating higher upstream pressure to a constant
lower downstream pressure. In most applications, the Pressure
Reducing function will be secondary to the primary Flow Control
Function.
The flow control action of the valve is controlled by a normally open,
differential control pilot designed to: 1) Open (allowing fluid out of the
main valve cover chamber) when the differential pressure across the
orifice plate is below it’s adjustable set point, and, 2) Close (allow-
ing fluid to fill the main valve cover chamber) when the differential
pressure across the orifice plate is above it’s adjustable set point.
A decrease in differential pressure causes the valve to modulate
towards an open position, increasing flow rate. An increase in differ-
ential pressure causes the valve to modulate towards a closed posi-
tion, decreasing flow rate.
1
X
X
X
Y/FC
P/L
4
5
3
2
CLOSES VALVE
OPENS VALVE
FLOW
(AOS)
The pressure reducing action of the valve 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.
The Orifice Plate Assembly should be installed three to five pipe diameters downstream of the Rate-of- Flow Valve, and field connected with
3/8
" minimum copper tubing in accordance with factory piping schematic.
Please specify desired flow rate PRIOR to ordering.
1 - Main Valve (M100 – Single Chamber)
2 - Rate-of-Flow Control
3 - Pressure Reducing Control Remote Sense
4 - Adjustable Closing Speed
5 - Orifice Plate Assembly
X - Isolation Cocks
1. Prior to installation, flush line to remove debris.
2. Install valve so the flow arrow matches flow through the line, and gauges to monitor valve inlet and outlet pressures. A Position Indicator
can be installed to provide visual indication of valve position and operation without disassembly.
3. Install isolation valves upstream and downstream of the main valve.
4. Provide adequate clearance for valve servicing and maintenance. Refer to valve servicing dimensions on next page. Avoid installing
valves 6" and larger in the vertical position (main valve stem horizontal). Automatic Control Valves (ACVs) are designed for horizontal in-
line installation, with the cover facing up (main valve stem vertical). Slow operation or premature stem and guide wear may occur if valve
is not installed according to factory recommendations. Consult factory for detailed engineering review prior to ordering if valve is to be
installed other than horizontally in-line.
5. If valve is equipped with a pilot control system, extra precautions should be made during installation to protect the piping circuit from
damage. Only remove the pilot control system from the valve if necessary. Tubing and fittings should be kept clean and replaced exactly
as removed. Consult appropriate hydraulic schematic to ensure proper re-assembly.
6. To accurately set flow rates, either a differential gauge or a flow meter should be installed.
7. Check orifice plate to assure that sense holes are free from obstruction.
8. After installation, vent entrapped air from valve cover and pilot system by following instructions on Technical Bulletin.
9. Install a pressure gauge at a location downstream of valve.
Start-up of an automatic control valve requires that proper procedures be followed. Time must be allowed for the valve to react to adjust-
ments and the system to stabilize. The objective is to bring the valve into service in a controlled manner to protect the system from damaging
over-pressure.
Installation
LFM114-2 (Globe) Rate-of-Flow Control Valve with Pressure
Reducing Feature
2 IOM-ACV-114-2_6114-2 2115
EDP# 1917073
© 2021 Watts
