Ames Fire & Waterworks 920GS-01 Stainless Steel Pressure Sustaining or Backpressure Control Valve with Hydraulic Check Feature - Manual

01/06
920 Series Model
8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.amesfirewater.com
Operation
The AMES Model 920-01 / 620-01 Combination Backpressure or Sustaining Control Valve with Hydraulic
Check Feature is designed to permit flow when upstream pressure is above the adjustable setpoint of the
control pilot, and throttle toward closed when upstream pressure falls below the adjustable setpoint, and
close drip-tight when downstream pressure becomes greater than upstream pressure.
It is controlled by a normally closed control pilot designed to: 1) Open (allowing fluid out of the main valve
cover chamber) when upstream pressure is above the adjustable setpoint, and, 2) Close (allowing fluid to
fill the main valve cover chamber) when upstream pressure is below the adjustable setpoint. An increase
in upstream pressure causes the valve to modulate toward an open position. A decrease in upstream
pressure causes the valve to modulate toward a closed position.
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 backpressure or
sustaining operation resumes when upstream pressure exceeds downstream pressure.
When the Model 920-01 / 620-01 is installed “in line” on the discharge of a pump, it acts as Backpressure
Control Valve. When pump discharge pressure falls below the pilot setting, the valve modulates toward a
closed position, increasing backpressure against the pump. The valve should be specified to include the
optional opening speed control when used for Backpressure applications.
When the Model 920-01 / 620-01 is located “in line” connecting two distribution zones, the valve acts as
a Pressure Sustaining Control Valve. When pressure in the upstream zone falls below the pilot setting,
the valve modulates toward a closed position, sustaining pressure in the upstream zone. The valve will
close, if necessary, until upstream pressure is above the pilot setting. The valve should be specified to
include the optional opening speed control and position indicator when used for Pressure Sustaining
applications.
BACKPRESSURE SUSTAINING VALVE
with HYDRAULIC CHECK FEATURE
920-01
620-01