Air To Close / Reverse Acting Positioner - GE Masoneilan 4700P Maintenance Manual

Air to Close / Reverse Acting Positioner

See Figure 19 on page 68.
1. Do not connect air supply or signal to the positioner. Valve is now open.
2. Note the valve position. The travel indicator should be approximately aligned with
the open end of the travel scale. If not aligned, consult proper valve instructions for
travel adjustment.
3. Place lever S/A (3) to proper side (left or right) as designated by the appropriate
cam selection table for valve in question.
4. Run an independent regulated air line to the valve actuator in place of positioner
output line. Slowly apply proper air pressure through the regulator to shut the
valve. Do not exceed designated supply pressure. (Handwheel may be used to
close the valve in place of regulated air line.)
5. With valve closed, place cam holder (36) with truarc ring (37) into cam coupling
(34).
6. Place the cam (26) into the cam holder (36) so that the selected cam lobe is facing
forward and will rest on the cam follower. Secure cam to cam holder with washer
(27) and screw (28). Tighten screw (28) while holding the cam (26).
7. With the valve closed, place the desired cam lobe's low signal line on the cam
follower. With the low signal line resting on the cam follower sight across the face
of the cam to the raised reference line on the positioner case and align. (Low
signal line and reference line.) Center cam between the two arms of the lever S/A
(3), then tighten set screws (35) to 87 inch-lbs. torque. (See Figure 19 on page 68 for
cam mounting.)
8. Slowly reduce pressure applied to actuator in Step 4 to zero. (If handwheel was
used to place valve in closed position, back it off completely.) Valve is now open.
Cam is at high signal line on lobe.
9. Disconnect the independent regulated air line to actuator and connect positioner
output line. Connect supply pressure and signal to positioner.
10. Adjust signal to low end of signal (i.e., 3 psig for a 3-15 psig range 4700P/4800P).
Adjust zero and span. Refer to "Zero Adjustment" on page 48 and "Span
Adjustment" on page 48.
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Masoneilan 4700P/E & 4800P/E Positioners Manual =| 53