17 of 18
Specifications subject to change without notice
Edition: August 2017
Maintenance EB 31a-01_EN
◦ Push and turn the housing onto the pistons clockwise
until the end of travel is reached. Check that the
internal angle adjusting screw does not reduce the
travel. This is not necessary if it is to be 90° to 95°.
◦ The shaft clearance is 3° to 5° more than 0°
(see Fig. 45).
Fig. 45
Fig. 46
•
Adjusting the opening angle for 0° position CLOSED
◦ To adjust, turn the adjusting screw ( 10a ) until the
required position is reached and lock this position with
the nut ( 12 ) using a socket wrench. While locking in
position, hold the adjusting screw stationary with an
Allen key.
◦ To ensure that both pistons stop at the same time, turn
the adjusting screw at the other piston until you feel
resistance and they stop at the shaft.
Lock the adjusting screw in the same position with the
lock nut ( 12 ).
◦ The initial position CLOSED has now been adjusted.
•
Mounting the end caps and compression springs
(see Fig. 46 and Fig. 47)
◦ Apply grease to the housing.
◦ Insert the correct number of compression springs
( 17 ) specified in Fig. 46 and according to the pattern
shown in Fig. 46.
◦ Fit on the end caps ( 3 ) and check to ensure that the
gaskets ( 14 ) are seated properly.
◦ Insert the screws ( 13 ) without screwing them tight.
Tighten them according to the sequence shown in
Fig. 47.
•
Adjusting the switching position to 90° position OPEN
(see Fig. 48)
◦ External adjustment can only be made after the
actuator assembly is completed with the pistons
extended as far as they will go on the outside of the
housing as shown in Fig. 48.
◦ In double-acting actuators, this can be done by turning
the shaft. When the actuator has been mounted onto
the valve, apply the control pressure to move it to this
switching position.
Once you have adjusted the switching position on one
side, turn the screw on the other side as far as it will
go and lock this position.
◦ For single-acting actuators (SRP), apply the control
pressure to move the actuator to the switching
position. Check this position, readjust, and move the
actuator to the position again until the required
position is reached.
◦ Lock the adjusting screw, while using an Allen key to
hold the screw stationary and lock it with a special key
(available from Pfeiffer).
The actuator assembly is now completed.
Fig. 47
Fig. 48
