VE VVG Electronic Two-way Valves
Technical Instructions
Document Number 155-112P25
Rev. 3 August, 2002
Page 4
Siemens Industry, Inc.
Warning/Caution Notations
WARNING:
Personal injury or loss of life may occur if you do not perform
a procedure as specified.
CAUTION:
Equipment damage may occur if you do not follow procedure
as specified.
Operation
The arrow on the valve indicates the direction of flow. The direction of flow is always
from II (A) to I (AB). See Figure 1
.
CAUTION:
Removing the bottom cap will not convert the two-way valve into a
three-way valve.
Figure 1. VVG Valve Direction of Flow.
An electronic motor actuator positions the valve. A continuous 0 to 10 Vdc signal
controls the actuator.
The valve provides a linear flow characteristic. A selector plug on the SQS… actuator
allows selection of linear or equal percentage flow characteristic. The valve stroke is
proportional to the control signal with linear flow selected. See Figure 4
.
A zero voltage control signal returns the valve to its "0" position. In the event of a power
failure, the SQS65U holds its last position, and the SQS65.5U returns the valve to its
fail-safe position.
The position output 0 to 10 Vdc signal "U" produces position feedback to the field panel.
An additive control input at R for 0 to 1000 ohms allows control by either a low
temperature detector or a remote setting unit.
Installation
•
The valve assembly can be installed in the supply or return line.
NOTE:
For hot water installations, it is recommended to place the valve in the return
line because the temperature is lower.
•
Match the direction of flow with the symbol cast on the valve body. See Figure 1
.
•
Allow 8 inches (200 mm) of clearance for installation and service.
