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2. Remove the stem connector clamps (7)
and the ring nut (8.2) from the actuator
(8). Slide the ring nut over the plug stem.
3. Place actuator onto the valve bonnet (5)
and secure with the ring nut (8.2).
4. Read bench range (or bench range with
pre-loaded springs) and fail-safe action
from the actuator's nameplate (e.g. 0.2
to 1 bar and "Actuator stem extends").
The lower value of the bench range
(0.2 bar) corresponds to the lower bench
range value to be adjusted; the upper bench
range value (1 bar) corresponds to the
upper bench range value. The fail-safe ac-
tion "Actuator stem extends" (FA) or "Actua-
tor stem retracts" (FE) is indicated on the
Type 3271 Actuator. The Type 3277 Actua-
tor bears the corresponding symbol.
5. For actuators with "Actuator stem ex-
tends", apply a signal pressure to the
lower diaphragm chamber which corre-
sponds to the lower bench range value
(e.g. 0.2 bar).
For actuators with "Actuator stem re-
tracts", apply a signal pressure to the
upper diaphragm chamber which corre-
sponds to the upper bench range value
(e.g. 1 bar).
6. Thread down the stem connector nut
(6.1) by hand until it makes contact with
the actuator stem (8.1). Then, turn it an-
other 1/4 turn and secure this position
with the lock nut (6.2).
7. Position the stem connector clamps (7)
and screw tight. Align the travel indica-
tor scale (5.3) with the tip of the stem
connector.
Assembling valve and actuator
Note on disassembling an actuator!
Before disassembling an actuator with
fail-safe action "Actuator stem extends" and
particularly an actuator with preloaded
springs, apply a pressure to the lower signal
pressure connection that slightly exceeds the
lower bench range value (see nameplate of
the actuator), so that you can loosen the ring
nut (8.2).
2.2
Pretensioning springs in
actuator version "Actuator
stem extends"
To achieve a greater positioning force, the
springs in actuators with "Actuator stem ex-
tends" can be preloaded with up to 12.5 %
(actuator sizes 120 and 240 cm²) or up to
25 % (350 cm² and higher) of their travel or
bench range.
Example:
If the springs are preloaded with, for exam-
ple, 0.1 bar for a bench range of 0.2 to
1 bar, the bench range is shifted by 0.1 bar
to result in a bench range of 0.3 to 1.1 bar
(0.1 bar corresponds to a preload of
12.5 %).
When adjusting the valve, the lower bench
range is to be set to 0.3 bar. Make sure the
new bench range of 0.3 to 1.1 bar is indi-
cated on the nameplate as the bench range
with preloaded springs!
7
EB 8015 EN
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