TWO-WAY FLOW ALTITUDE VALVE
01/05
F127-2 (Globe)
Classic Series
Operation
The Watts ACV Two Way Flow Altitude Valve is designed to open, allowing flow into a reservoir or elevated
storage tank (tank fill), and close drip tight when high water level is achieved. The valve also opens, allowing
return flow (tank discharge), when upstream pressure falls below reservoir head pressure. The Altitude Pilot
remotely senses static tank head pressure (water level) through a field installed sensing line, and directs
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 (dry drain) or to atmosphere (wet
drain), causing the valve to open fully. 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.
As water level decreases, static tank head pressure falls below the adjustable setpoint of the Altitude Pilot,
causing it to pressurize the cover of the Accelerator Pilot, opening the valve. As water level increases, static
tank head exceeds the adjustable setpoint of the Altitude Pilot, causing it to depressurize the cover of the
Accelerator Pilot, closing the valve drip tight. Valve opening and closing speeds are separately adjustable.
The Position Indicator with Air Bleed Petcock allow for visual indication of valve position and easy venting of
air entrapped in the main valve cover chamber.
F1127-2 (Angle)
When upstream pressure falls below reservoir head pressure, a Check Valve installed in the pilot control
system “Return Flow Line” opens, connecting the main valve cover chamber to the upstream pressure
zone, causing the valve to open allowing reservoir pressure to return into the upstream pressure zone (Tank
Discharge).
Specify Tank height PRIOR to ordering.
8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.wattsacv.com
TWO-WAY FLOW ALTITUDE VALVE
01/05
F127-2 (Globe)
Classic Series
Installation Guidelines
• Prior to installation, flush line to remove debris.
• Install valve horizontally “in line” (cover facing UP), so flow arrow matches flow through the line. Avoid
installing valve 6” and larger vertically. Consult factory prior to ordering if installation is other than
described.
• Install inlet and outlet isolation valves. NOTE: When using butterfly valves, insure disc does not contact
control valve. Damage or improper valve seating may occur.
• Provide adequate clearance for valve servicing and maintenance.
• Install pressure gauges to monitor valve inlet, outlet, and static head pressure.
• Provide adequate drain for cover chamber discharge if “wet drain” option is selected. Consult “Valve
Cover Capacity” chart on appropriate main valve Engineering Bulletin.
• Install static tank head sense line. For optimum control, sense line should be: 1) Installed with an
upward angle (towards reservoir) to avoid air accumulation, 2) Connected no further than forty-five pipe
diameters from the reservoir, and 3) A minimum of 1/2” diameter.
F1127-2 (Angle)
Other Watts ACV Altitude Control Valves
F127-1 / F1127-1 One Way Flow Altitude Valve
F127-8 / F1127-8 One Way Flow Altitude Valve with Pressure Sustaining Feature
F127-11 / F1127-11 One Way Flow Altitude Valve with Delayed Opening Feature
F127-31 / F1127-31 Two Way Flow Altitude Valve with Solenoid Override Feature
F127-32 / F1127-32 One Way Flow Altitude Valve with Solenoid Override Feature
8550 Hansen Road • Houston, Texas 77075 • (Ph) 713.943.0688 • (Fx) 713.944.9445 • www.wattsacv.com