CRANE
CO.
280
N.
MIDLAND
AVE.,
STE
258,
SADDLE
BROOK,
NJ
07663
WWW.AVIDCONTROLS.COM
12/17/12
TECH-440/D.W.O. 23135
Page 44 of 55
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 (such
as Stoddard solution or volatile mineral spirits). To clean the spool, use a clean lint
free cloth. To clean the I.D. of the sleeve a polyester lint free clean room swab is
MANIFOLD FILTER HOLDER
WITH O-RING
AIR FILTER
MS-10222