2
VA-8122 Proportional Valve Actuator Product/Technical Bulletin
O
peration
The actuator uses a reversible synchronous motor to
accurately position the valve. The motor can reliably
generate 22 pounds of force in either the Drive Down
(DD) or Drive Up (DU) direction.
Once the valve closes, a shutoff force builds up. When
this force reaches 22 pounds, a lever within the
actuator operates a force sensor that stops the motor.
The constant load at the end of travel ensures tight
valve seat shutoff and compensates for seat wear.
Field calibration of shutoff is not required. The actuator
maintains the shutoff force and its last position even if
power is removed.
Note:
The valve stem can be positioned manually by
turning the manual adjustment knob shown in
Figure 2. Rotating the knob counterclockwise
moves the valve stem up.
Yoke/
Machine Screw
Lever
Plate
Drive
Screw
Jumpers
W1-W5
AUTOCAL
Pushbutton
Spade
Terminals (3)
LED
Circuit Board
+
2
4
C
O
M
V
D
C
/m
A
Stem Retainer/
Position Indicator
Manual
Adjustment
Knob
Figure 2: VA-8122 Components
IMPORTANT:
There are no internal mechanical
stops in the actuator. Never drive
the actuator unless it is installed on
the proper valve body, or the
actuator may be damaged.
D
imensions
See Figure 3 for actuator dimensions.
5.00
127.0
2.50
63.5
0.87
22.2
4.50
114.3
0.50*
12.7
2.50*
63.5
* Required for cover
removal clearance.
Figure 3: VA-8122 Dimensions, in. (mm)
I
nstallation
IMPORTANT:
Dripping water must be prevented
from entering the actuator housing,
since this could damage the
actuator. Do not cover the actuator
with thermal insulating material.
Note:
The VA-8020-100 kit (ordered separately) is
required if mounting to a VT Series Terminal
Unit Valve.
Kit Includes
•
VA-8122 actuator
•
VA-8020-605 stem retainer and clip kit
Tools Required
•
5/16 in. (8 mm) nut driver or 3/16 in. (5 mm)
flat-blade screwdriver
•
needle-nose pliers
•
crescent wrench (to fit 1-1/4 in. bonnet
adaptor nut)
