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3710 and 3720 Positioners
5. Secure the assembly with the four machine
screws (key 3).
Assembling the Spool Valve, Action
Block, and Gasket
WARNING
Refer to the WARNING at the
beginning of the Maintenance section
of this manual.
1. Place the action block gasket (key 29) on the
mounting area found on the positioner base plate.
Place the action block (key 28) on the gasket and
secure it to the base plate using the four machine
screws (key 3).
2. Inspect the three O-rings (key 2) found between
the spool valve (key 1) and the action block. Replace
the O-rings, if necessary.
See figure 26. Handle the spool valve
body and spool with care. The body
and spool are manufactured to precise
tolerances and are prepared as a
matched set.
3. Be sure the spool valve is ready for service.
Clean or replace it, if necessary.
See figure 30. Before securing the
spool valve, make sure the spool head
makes proper contact with the end of
the summing beam.
4. See figure 30. Position the spool valve on the
action block. Make sure the spool extending from the
spool valve body properly engages the summing
beam. Start the two machine screws (key 3) so the
spool valve is loosely held in position on the action
block.
5. Before tightening the machine screws holding
the spool valve, make sure the end of the
summing beam does not contact the spool.
Rather, the summing beam should contact the spool
head. If necessary, adjust the position of the spool
valve on top of the action block, making sure the
summing beam does not bind on the spool
throughout the full travel of the summing beam.
Tighten the two machine screws.
36
Note
Note
6. Be sure the spool head and summing beam
remain engaged, but do not bind up, over the entire
operating range of the input module.
Assembling the Feedback Shaft
(Cam Shaft)
WARNING
Refer to the WARNING at the
beginning of the Maintenance section
of this manual.
1. Inspect the feedback shaft (key 38). Be sure the
shaft is free from any damage. Inspect the flanged
bearings (key 17) and spacer (key 69). Replace, if
necessary.
2. Properly install the flanged bearings in the
positioner base plate. Install the spacer on the
feedback shaft. Insert the shaft with spacer through
the bearings and base plate. Make sure the
feedback shaft rotates freely.
3. Install the washer (key 39) and retaining ring
(e-clip) (key 40) that hold the feedback shaft in
place.
4. Attach the cam (key 36) and cam locknut
(key 37).
5. Set the initial cam position following the
procedures given in this manual, if necessary.
Replacing the Feedback Arm Assembly
and Span Adjuster Assembly
WARNING
Refer to the WARNING at the
beginning of the Maintenance section
of this manual.
The zero adjustment locknut and zero
adjustment knob are identical parts,
key 35.
To identify the span adjuster assembly
for 0.4 to 2.0 bar (6 to 30 psig) input
range, red color coding appears on the
range spring.
1. Make sure the zero adjustment knob (key 35) is
installed on the span adjustment shaft (threaded rod)
Instruction Manual
Form 5300
July 2005
Note
Note
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