MAINTENANCE
PREVENTIVE MAINTENANCE PROCEDURES
7 - 2
PREVENTIVE MAINTENANCE PROCEDURES
This section covers instructions for cleaning and replacing the
manifold filters.
MANIFOLD FILTERS
Tools Required:
• Torque screw driver.
1. Transfer the positioner from automatic to manual operation
(Section 5).
2. After allowing the pressure to bleed off, remove the cover
screw securing the filter cover (Fig. 7-1) and set the cover screw
and cover aside.
3. Clean or replace the filters.
a. To clean the filters, soak them in a low residue solvent.
After soaking, spray the filters thoroughly using compressed
air until they are free of particles and solvents.
b. Insert the clean or new filters, using the filter kit identified
in Table 1-7, into the filter wells.
4. Replace and lubricate the three O-rings (Fig. 7-2) using the
lubricant supplied in the kit (Dow Corning
®
No. 4).
5. Clean and place the cover over the filters and replace the
cover screw. Torque the cover screw to two Nm (18 in-lbs).
Check all air connections for leakage while positioner
is under pressure. Use a soapsuds solution.
12
Check the signal diaphragm for leaks. use a soapsuds
solution.
Clean pilot valve and stem with low residue solvent.
Refer to REPAIR AND REPLACEMENT in Section 8.
Check calibration of positioner and actuator. Refer to
Section 4.
Check and verify that there is no backlash in the link-
age/connections between the positioner and the actu-
ator. Refer to Section 3.
Table 7-1. Preventive Maintenance Schedule (continued)
Preventive Maintenance Tasks
Interval
(months)
WARNING
Lock the actuator in place or be aware of the possible move-
ment before moving the equalizing valve to MAN or AUTO.
Failure to do so could result in injury to personnel.
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