THD SERIES S11-S27 HEAVY DUTY ACTUATORS
Installation & Maintenance Manual
4
September 25, 2015
www.atcontrols.com
documents\products\IOM\IOM8036
9. Converting from Double Acting to Spring
Return
!!!WARNING!!!
FOR YOUR SAFETY,
IT IS IMPORTANT THAT BEFORE
REMOVING ANY COMPONENTS OF THE ACTUATOR,
ENSURE THAT ALL PNEUMATIC AND ELECTRICAL
SUPPLIES ARE DISCONNECTED AND LOCKOUT AND
TAGOUT PROCEDURES ARE IMPLEMENTED.
1.
Disconnect electrical supplies and shut off pneumatic
supply, vent actuator and remove from valve or damper.
2.
Remove the stop bolt cap on the end cap of the air
cylinder and loosen the hex nut and back out the stop bolt.
The stop bolt must be backed off so that when 10 psig of
air is applied to the adapter there is no load on the stop
bolt.
3.
Remove the cover bolts and clean out the jacking screw
holes. Install a bolt into each jacking screw hole and
alternately tighten the screws to bring the cover plate up
so that it can be removed from the yoke bearing.
4.
Remove the end plate (item 35) also remove the stop bolt
cover, hex nut and stop bolt as these will be used in the
spring cartridge on models S16 thru S27.
5.
Remove the set screws holding the stop screw pad in the
sliding block (item 22).
6.
Remove the stop screw pad.
7.
Install the spring pusher rod into the spring cartridge.
8.
Place a light coat of blue permantex on the flange gasket
and apply to the actuator.
9.
Lift Spring Cartridge and slide spring pusher rod into
access hole and into hole in the sliding block.
10.
Install the 4 cap screws and lock washers provided with
the spring cartridge.
11.
Place a light coating of permantex blue on cover gasket
and install. Place cover over the alignment pins and install
bolts and tighten. Remove any excess gasket sealer after it
is dry.
12.
Install indicator plate and tighten bolts.
13.
Install stop bolt and hex nut in rear of spring
cartridge.(models S16 thru S27)
14.
Apply air pressure and check for smooth operation.
15.
Adjust both stop bolts as necessary for proper travel and
check for leakage before installing stop bolt covers.
10. Changing from “Spring Closed” to “Spring
Open”
To convert from spring closed to spring open requires that the
air cylinder be removed and the spring cartridge removed and
placed on the opposite side of the actuator. Complete
instructions for rebuilding the air cylinder are listed above
along with instructions for installing the spring
11. Seal kits and Repair Parts
To order replacement seal kits or spare parts please provide
the following information:
Actuator Model Number
Serial Number
Type of seal kit (Nitrile standard, low temperature, Viton
Item Number, Description and quantity for repair parts.
