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GE Oil & Gas
5.8 CONVERTING A 7700P POSITIONER (PNEUMATIC)
INTO A 7700E POSITIONER (ELECTROPNEUMATIC)
A kit comprising the manifold block (144) and the I/P
module (20) is available from your local Masoneilan
representative or the Spare Parts Department.
REFER TO ATEX INSTRUCTION MANUAL
No. 185977 FOR ALL MAINTENANCE ON
THE ELECTRICAL PARTS OF THE 7700E
POSITIONER.
Shut off the signal and supply pressure. Isolate and
depressurize the valve body.
A. Disconnect the two pressure connection nuts (138a)
and pull the tubing (140) out.
B. Loosen the two cap screws (141a) and remove
manifold block (144). The spring (158), gasket (146)
and the three O-rings, the pilot valve assembly (155
to 157), shims (145), and O-ring (153) do not need to
be removed unless you have new parts. Otherwise,
simply check that parts are in perfect condition
before refitting.
Caution: Handle the shims carefully (145).
C. If the parts mentioned above have been removed,
proceed as follows:
Fit the O-ring (153), shims (145), pilot valve assembly (155
to 157), gasket (146) and the three O-rings, the spring
(158) and manifold block (144) - I/P module (20). Tighten
screws (141a), refit tubing (140) and tighten pressure
connection nuts (138a).
Note: The ports in gasket (146) must be aligned with
those in positioner block (147).
To ensure correct positioner performance, check that all
gaskets are perfectly leaktight.
D. Hook spring clamp (115) to lever (22) (VariPak 28002)
or (113) (VariPak 28001). In the case of VariPack
28001 valve, see figure 6 to position the spring clamp
(115) according to the actuator required action.
Admit the supply pressure and enable the electrical
signal. Adjust the start-up pressure following the
instructions under "Calibration". Put back into service.
