Flowrite VF599 Series Three-Way Valves
Technical Instructions
2-1/2 to 6-inch Flanged Iron Body
Document Number 155-160P25
June 10, 2003
Siemens Industry, Inc.
Page 7
Figure 3. Close-off Pressures.
Operation
This Flowrite three-way valve is designed as a mixing
valve.
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. Non-spring
return actuators will hold the last commanded
position. See the Technical Instructions of the
various actuators for additional information.
If this valve is used in diverting applications, the
following conditions apply:
Diverting service with modulating control can only
use the electro-hydraulic actuator, SKB/C. 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.
Figure 4. Three-Way Valve
Operation as a Mixing Valve.