User Manual

IOM-9540R14
VII. TROUBLE SHOOTING GUIDE
1. Actuator does not respond to applied input signal.
Possible Causes Remedies
A. Amplifier defective A1. Replace amplifier (See VI.C.).
B. Pneumatic connections reversed B1. Check connections.
C. Feedback lever not tightened C1. Screw feedback lever tight (See III.D.9.).
D. Stroke factor lever is loose on the shaft D1. Tighten shaft.
E. Positioner mounted on the wrong side E1. Check mounting side in accordance with table in Section III.
F. Changeover plate in the wrong direction F1. Check setting in accordance with table in Section III.
2. Output pressure does not reach its maximum.
Possible Causes Remedies
A. Amplifier throttle dirty A1. Remove and clean throttle (See VI.B.).
B. Supply air too low B1. Check supply air pressure.
C. Flappers not parallel with nozzles C1. Align flappers (See VI.A.3.d.-f.).
D. Supply air filter dirty D1. Replace filter.
3. Actuator moves to end position.
Possible Causes Remedies
A. Positioner mounted on wrong side A1. Check mounting side in accordance with table in Section III.
B. Feedback lever not tightened B1. Tighten feedback lever.
C. Stroke factor lever loose on shaft C1. Tighten shaft (See III.B.).
4. Unstable behavior; non-steady state in control loop.
Possible Causes Remedies
A. Amplification too high A1. Reduce amplification.
B. Gland friction on the valve too high B1. Loosen gland packing somewhat or replace.
C. Mislocated Cam C1. Loosen cam and relocate follower out of “valley” and
higher up on lobe.
5. Stroke range cannot be adjusted.
Possible Causes Remedies
A. Wrong range spring A1. Replace range spring (See IV.D.).
B. Positioner does not completely reduce B1. Check supply air pressure.
pressure B2. Check amplification.
B3. Adjust clearance between nozzle and flapper.
6. Positioner makes “buzzing” noise.
Possible Causes Remedies
A. Wrong action setting A1. Check the position of the bypass switch and the action.
Change as required.
SECTION VII