Specifications

WESTLOCK CONTROLS CORPORATION
280 MIDLAND AVENUE, SADDLE BROOK, NJ 07663 TEL: [phone] FAX: [phone]
www.westlockcontrols.com
1/12/10 TECH-439/D.W.O. 19024 Page 47 of 58
Appendix E
General Maintenance Standard Flow
The positioner’s onboard filter should be replaced regularly or whenever it gets
clogged. See diagram below for location of the filter. Note: the following
instructions are for Standard Flow. For High Flow please contact the factory.
Important: The positioner’s onboard filter is not a substitute for normal
instrument air preparation. Supply air to the positioner should conform to ISA
Standard S7.3 - Quality for Instrument Air.
Important: The filter’s original color is chalk white. If the filter is discolored, its
replacement should be performed more often. A discolored filter may also
indicate the need for an evaluation of the air-supply quality. A filter/regulator with
a 5 micron or better element, just prior to the positioner, is therefore
recommended.
Spool valve cleaning
In favorable conditions (i.e. high quality supply air, healthy actuator) there will be
minimal if any maintenance necessary on the spool valve. If unfavorable
conditions exist (i.e. poor supply air quality or if lubrication and sediment from the
actuator is being exhausted through the spool valve) it may become necessary to
clean the spool valve to avoid operational failures due to valve sticking and to
maintain optimum positioner performance.
To clean the spool valve, the spool piece needs to be removed (see following
diagram). Prior to removing the spool, make sure the positioner is out of service
and all air pressure has been bled-off the positioner and the actuator. The spool
piece and sleeve can be cleaned using any non-chlorinated cleaning solvent. To
clean the spool, use a clean lint free cloth. To clean the I.D. of the sleeve a