Ames Fire & Waterworks 972GS-20 Stainless Steel On-Off Float Valve with Pressure Sustaining Feature User Manual
970 series, Model
01/06
970 Series
Model
8550 Hansen Road
•
Houston, Texas 77075
•
(Ph) 713.943.0688
•
(Fx) 713.944.9445
•
www.amesfirewater.com
ON-OFF FLOAT VALVE with
PRESSURE SUSTAINING FEATURE
972-20
672-20
Operation
The AMES Model 972-20 / 672-20 On-Off Float Control Valve with Pressure Sustaining Feature is designed
to open fully or close drip-tight as commanded by the Float Control Pilot. The Float Pilot may be either valve
or remote mounted. The valve closes drip tight when water level reaches the adjustable high-level setpoint,
and opens fully when water level is below the adjustable low-level setpoint, allowing a calculated “draw-
down” of water level to increase tank circulation. The valve will also throttle to sustain a minimum upstream
pressure during tank filling operations.
The On-Off Float Pilot directs upstream pressure into and out of the cover chamber of the 3-way Accelerator
Pilot. When the cover of the Accelerator Pilot is pressurized, the main valve cover chamber is vented
downstream, causing the valve to open. When the cover of the Accelerator Pilot is de-pressurized, the
main valve cover chamber is connected to upstream pressure, causing the valve to close drip tight. Valve
opening and closing speeds are separately adjustable. When water level reaches the adjustable high-level
setpoint, the Float Pilot de-pressurizes the cover chamber of the 3-Way Accelerator, closing the valve drip
tight. The valve remains closed as water level decreases. When water level reaches the adjustable low-
level setpoint, the Float Pilot pressurizes the cover chamber of the 3-Way Accelerator, opening the valve.
High and low levels are separately adjustable by positioning stop collars on the float rod(s) at desired
opening and closing setpoints.
The normally closed sustaining pilot remains open when upstream pressure is above the adjustable setpoint,
and modulates toward a closed position if upstream pressure falls below the setpoint. As the sustaining pilot
closes, fluid is directed into the main valve cover chamber, allowing the valve to modulate toward a closed
position, raising upstream pressure. Normal on-off float control operation resumes when upstream pressure
is above the sustaining pilot setpoint.