Standard Components
Operation
The Combination Pressure Reducing and Check Automatic Control
Valve (ACV) is designed to automatically reduce a fluctuating higher
upstream pressure to a constant lower downstream pressure, and
close drip-tight when downstream pressure becomes greater than
upstream pressure.
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.
If downstream pressure becomes greater than upstream pressure,
downstream pressure is admitted to the main valve cover chamber,
closing the valve and preventing reversal of flow. Normal pressure
reducing operation resumes when upstream pressure exceeds
downstream pressure.
1
X
X
X
X
Y/FC
P/L
AOS
3
4
3
CLOSES VALVE
OPENS VALVE
FLOW
2
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 Indi-
cator 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. Open the isolation ball valves in the control tubing if so equipped. Failure to open these will prevent the valve from functioning properly.
Note:
If using butterfly valves, ensure valve disc does not contact the main valve.
5. Provide adequate clearance for valve servicing and maintenance. Refer to valve servicing dimensions on next page.
6. Avoid installing valves 6" and larger in the vertical position (main valve stem horizontal). Automatic Control Valves (ACVs) are de-
signed 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.
7. 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.
8. After installation, vent entrapped air from valve cover and pilot system by following instructions on Technical Bulletin.
Start-up of an automatic control valve requires that proper procedures be followed. Time must be allowed for the valve to react to ad-
justments 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.
1 – Main Valve (905GD - Single Chamber)
2 – Pressure Reducing Control
3 – Check Valve
4 – Fixed Orifice
X – Isolation Cocks
Installation
910GD-01 (Globe) Pressure Reducing Control Valve with
Hydraulic Check Feature
2 IOM-A-ACV-910-01_610-01 2115
EDP# 1917030
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