Install Instructions
Document No. 129-215
Installation Instructions
September 29, 2009
Page 6 of 9 Siemens Industry, Inc.
Installation, Continued
Spring adjustment
The top edge of the stem nut measures the valve
stem position. The “0” marking on the actuator yoke
indicates stem up position. The “1” mark indicates
stem down position.
With the actuator in an upright position and the stem
visible as shown in Figure 11, use a 1-1/16 inch
open-end wrench to turn the adjustment screw.
For Normally Open Valves: To increase the
start to close pressure, turn the adjustment
screw from right to left. To decrease, turn
the adjustment screw from left to right.
Normally Closed Valves: To increase the
start to open pressure, turn the adjustment
screw from right to left. To decrease, turn
the adjustment screw from left to right.
NOTE: As the line pressure differential across the
valve increases, the spring span will
increase.
SKB/C Actuators
0
1
24 mm
EA0236R1
Figure 14. SKB/C Actuators.
Tools
1-inch open-end wrench
24 mm open-end wrench
3/8-inch open-end wrench
CAUTION:
Do not damage or scratch the polished
surface of the valve stem.
Removing the actuator
1. Turn off the power to the actuator.
2. Use a 24 mm open-end wrench to loosen the
stem nut from the actuator shaft.
3. Lower the valve stem to avoid damaging the
valve stem.
4. Use a 3/8-inch open-end wrench to loosen the
actuator retainer screws and remove the
actuator retainer. See Figure 9.
5. Remove the actuator from the valve bonnet.
6. Remove and retain the stem retainer clip and
stem nut from the valve stem. See Figure 15.
Figure 15. Stem Nut and Stem Retainer Clip.
7. Return to the instructions for Removing the
packing cartridge.
Assembling the actuator to the valve
1. Place the stem nut over the valve stem and
attach the stem retainer clip. See Figure 15.
2. Place the actuator onto the valve bonnet, and
fasten it with the actuator retainer.
3. Use a 3/8-inch wrench to tighten the actuator
retainer screws.
4. Raise the valve stem so that the stem nut can
be fastened to the stem adapter.
5. Tighten the stem nut with a 24 mm wrench.