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Specifications subject to change without notice
Edition: August 2017
Maintenance EB 31a-01_EN
6.1.2
Disassembly of the actuator:
When the actuator must be disassembled for maintenance
purposes, first remove the actuator from the valve.
Note:
Before disassembly, it is important to check
that the actuator is not pressurized and the
compression is relieved from the actuator springs
(end position).
Always use caution and check that ports 2 and 4 are vented
and that all accessories are removed.
Before disassembling a single-acting actuator, make sure that
the actuator is in the start position and the pistons fully
retracted.
•
Removing the position indicator
(see Fig. 16)
◦ Remove screw ( 24 ).
◦ Lift position indicator ( 19 ) from shaft. If necessary,
use a screwdriver to lever it off.
•
Removing the adjusting screws:
(actuator versions manufactured
up to 2006
) (see Fig. 17)
◦ Remove both adjusting screws ( 2 ) with the washers
( 4 ) and lock nuts ( 3 ).
◦ Remove O-rings ( 11 ) and replace them when
replacing spare parts.
•
Removing adjusting screws:
(actuator versions manufactured
from 2006
) (see Fig. 17)
◦ Remove lock nuts ( 3 ) together with washers ( 4 ).
◦ Remove O-rings ( 11 ) and renew them when
replacing spare parts
◦ Unthread both adjusting screws ( 2 ) and continue
unscrewing until their stopping point. Before
continuing with the final disassembly, remove the end
caps ( 22 and 23 ) and the pistons ( 25 ) since the
adjusting screws can only be removed from the inside
of the housing. The instructions for dismantling the
end caps and pistons are described below.
•
Removing the end caps
(see Fig. 18)
For sizes 900 to 3000, the end caps ( 22 and 23 ) are
symmetric.
◦ Remove the screws ( 13 ) in the sequence a-b-c-d
(see Fig. 18).
Note:
When disassembling a single-acting
actuator, loosen the screws of the end caps ( 22
and 23 ) in alternating sequence.
If there is still noticable force after 4 or 5 turns on all end cap
screws, this may indicate a damaged spring cartridge, and
any further disassembly should be discontinued. Further
disassambly of the end caps may result in injury.
Return the actuator to Pfeiffer for further maintenance.
◦ For single-acting actuators, remove spring cartridge
( 17 ).
◦ Remove gasket ( 14 ) and renew it when replacing
spare parts.
Fig. 16
Fig. 17
Fig. 18
