Maintenance/Conversion; Inspection; Maintenance; Replacing Entire Actuator Or Fitting - ABB 23/26 Instructions De Service

4

Maintenance/conversion

4.1

Inspection

Within the the framework of inspection, the functional capabilities must be checked, especially to verify whether stroke 0
... 100 % is being fully controlled (see table page GB 8), nominal setpoint stroke in mm.
Apart from faults in the positioner (see Operating Instructions for positioner), leaks, e.g. a leak in the spindle sealing or a
torn diaphragm in the actuator could adversely affect the full control.
Moreover, the housing seals as well as the composition of the sealing surfaces of the seat and cone must be checked in
the course of inspection.
4.2

Maintenance

Regular maintenance is not necessary.
4.3

Replacing entire actuator or fitting

(see also the figures on page GB 10 and page GB 11).
To fully replace the actuator or the fitting, both units must be separated from each other.
Proceed as follows to dismantle or mount subsequently:
a) Bring the control valve to the fully opened position. This is the default setting for direction of action "air closes/spring
force opens". A full positioning signal has to be issued for the direction of action "air opens/spring force closes".
b) Open spindle coupling by unscrewing 2 screws (33).
c) Push the valve spindle (105) downwards (cone on the seat), undo the lock nut (30), unscrew the stroke display (34)
and the lock nut (30) from the spindle.
d) Sever the clamp ring connection (114) at the connection between the actuator lantern (14) and the actuator yoke and
the base flange (107) and remove the actuator.
e) When replacing the actuator, if applicable remove the attached positioner and fit it to the new actuator.
f) Mount while proceeding in the reverse order.
Caution!
!
Having completed these tasks, make sure that the seat and cone close properly and that setpoint stroke
complies with the specifications on the nameplate. In the end position "closed", cone must be definitely
hit against the seat.
Adjustment or corrective measures can be carried out on the spindle coupling (30...34) by changing the
screwed depth of the spindles (12 + 105) in the coupling halfs.
4.4

Changing the direction of action of the actuator

(only possible in version "F")(see also the figures on page GB 10 and page GB 11).
A distinction must be made between the following 2 directions of action:
"Air opens/spring force closes"
and
"Air closes/spring force opens"
Conversion can be effected at a later date, proceeding as follows:
Conversion from "air opens/spring force closes" in "air closes/spring force opens"
a) Interrupt the supply air intake to the positioner.
b) Unscrew the cables and piping on the positioner and remove positioner (see Operating Instructions for the posi
tioner).
c) Unscrew the closing screw (25 ) and remove seal (24).
d) Remove water protection cap (23), unscrew closing screw (48) and remove seal (20).
e) Turn the air reverse screw (52) up to upper limit stop.
f) Unscrew nut (13) through the open cap (7) from the spindle.
g) Unscrew screws (61) and remove diaphragm compartment.
h) Unscrew bushing (15), remove seal (18) and mount both of them again on the opposite side of the diaphragm cham
ber.
i) Mount the diaphragm while working in the reverse order.
j) Finally, screw the closing screw (48) onto the screw sleeve (22).
Conversion from "air closes/spring force opens " in "Air opens/spring force closes"
Proceed as already described:
42/13 20 XB Control Valves 23/26 GB 5