Table of Contents
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INTRODUCTION
WARNING
Error
Oscillation of actuator
Actuator at one end of
stroke and does not
respond to input change
SECTION 6 - TROUBLESHOOTING
This section provides the operator with information about the Type
AV positioner when operating difficulties are encountered. A table
listing errors, probable causes, and corrective actions allows the
operator to troubleshoot a problem pertaining to the positioner.
Make certain the positioner is disconnected from the supply
pressure source and the signal source or is removed from
service before attempting any repair or replacement proce-
dures. Failure to do so could cause unexpected movement
of the actuator and bodily injury could result.
If a problem occurs and is traced to the positioner, check supply
pressure, input and output connections, and mechanical adjust-
ments before removing from service.
Table 6-1. Positioner Errors
Probable Cause
Gain too high.
Drive arm not securely
attached to actuator.
Servo assembly unsta-
ble - gain too high.
Pneumatic signal leak.
Pilot valve stuck.
Air lines in wrong ports. Check air line connections. Refer to Figures
Incorrect cam installed
for application.
Corrective Action
Change gain hinge spring to greater thickness.
Refer to
GAIN HINGE SPRING
Tighten or correct linkage as necessary.
Adjust servo gain. Refer to
SHOOTING CALIBRATION ADJUSTMENTS
in Section 4.
Check for leaks in connectors or fittings.
Remove pilot valve and clean or replace. Refer
to
PILOT VALVE BODY
3-8
and 3-9.
Determine application (reverse or direct-act-
ing) and check for correct cam. Refer to Fig-
ures
3-8
and 3-9.
in Section 8.
TROUBLE-
in Section 8.
INTRODUCTION
6 - 1
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Table of Contents
Troubleshooting
