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Section 5
Maintenance
Inspection and Maintenance
WARNING
The following maintenance procedures
require taking the controller out of ser-
vice. To avoid personal injury and prop-
erty damage caused by uncontrolled
process pressure, provide some tempo-
rary means of control for the process
before taking the controller out of ser-
vice.
Before performing any maintenance op-
erations:
Shut off the supply pressure to the
controller.
Disconnect any operating lines pro-
viding supply air pressure, a process
input signal, or other pressure source to
the controller.
Unless otherwise noted, key numbers
refer to figures 5–24 through 5–32. Fig-
ures 3–1 and 3–3 show adjustment loca-
tions for 4195KA Series controllers. Fig-
ures 4–1 and 4–3 show adjustment
locations for 4195KB and KC Series
controllers For maintenance on the indi-
cator assembly, refer to figures 5–25
through 5–28.
Controller parts are subject to normal wear and must
be inspected and replaced as necessary. The frequen-
cy of inspection and parts replacement depends upon
the severity of the service conditions. When inspection
or repairs are required, disassemble only those parts
necessary to accomplish the job.
Because of the care Fisher Controls takes in meeting
all manufacturing requirements (heat treating, dimen-
sional tolerances, materials of construction, and other
product characteristics specified by Fisher Controls),
use only replacement parts manufactured or furnished
by Fisher Controls.
Select the appropriate maintenance procedure and
perform the numbered steps. Each procedure requires
that the supply pressure be shut off before beginning
maintenance.
The maintenance procedures section describes part
replacement common to 4195KA, KB, and KC Series
Note
4195KA, KB, and KC Series
controllers. After completing the maintenance proce-
dures, perform the appropriate calibration procedures.
Unless otherwise noted, calibration procedures for the
4195KA Series controller are in Section 3; calibration
procedures for the 4195KB and KC Series controller
are in Section 4. If difficulty is encountered performing
the calibration procedures in Section 3 or 4, refer to
the calibration procedures in this section.
Troubleshooting
As an aid to troubleshooting, table 5–1 lists some
common operating faults, their probable cause, and
suggests procedures for correcting the faults.
Replacing Common Controller Parts
To avoid personal injury or property
damage caused by the uncontrolled re-
lease of pressure, be sure any trapped
process pressure is properly vented
from the controller. Vent any supply
pressure from the controller before dis-
assembly.
Replacing the Process Pressure Scale
To prevent the pointer or set point indi-
cator from rubbing on the cover or scale
and producing an inaccurate indication,
take care not to bend the process point-
er or the set point indicator while per-
forming the following procedure.
Refer to figure 5–1.
1. Adjust the set point indicator (either manually or
with the remote set point pressure) to the mid-scale
mark on the process scale.
2. Remove the four self-tapping screws (key 37).
WARNING
CAUTION
5–1
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