Data Sheet for Product

Flowrite 599 Series Three-Way Valves Technical Instructions
Document Number 155-185P25
June 10, 2019
Siemens Industry, Inc. Page 7
ELECTRICAL PNEUMATIC
Figure 3. Close-off Pressures.
Operation
As the valve stem moves downward, the flow
through the NO port decreases and the flow
through the NC port increases. As the valve stem
moves upward, the flow through the NO port
increases and the flow through the NC port
decreases.
In the event of power failure, a spring return
actuator returns the valve to its normal position with
the upper port closed and the bottom port open.
Non-spring return actuators will hold the last
commanded position. See the Technical
Instructions of the various actuators for additional
information.
Figure 4.
If this valve is used in diverting applications, the following conditions apply:
Diverting service with modulating control can use mechanical actuators such as the
SAX and SKB/D. The differential pressure must not exceed 90% of the maximum
differential pressure specified for the three-way valve in mixing service.
Diverting service with a pneumatic actuator can only be used with two-position control.
To change over from one port to another there must be no system pressure. The pump
is turned off.