IOM-123-1+6 +S DIFF
6
SECTION VII
VII. TROUBLE SHOOTING GUIDE
1. Erratic Operation; chattering
Possible Causes
Remedies
A. Oversized regulator.
A1. Check actual flow conditions, resize regulator for minimum and
maximum flow.
A2. Increase flow rate.
A3. Install next step higher range spring. Contact factory.
A4. Before replacing regulator, contact factory.
B. Inadequate rangeability.
B1. Increase flow rate.
B2. Decrease regulator pressure drop.
B3. Install next step higher range spring. Contact factory.
C. Worn piston/cylinder; inadequate guiding.
C. Replace trim.
D. Unstable loading pressure.
D1. Stabilize loading pressure; i.e. pump, control, valve, etc.
D2. Air in loading piping in liquid service. Vent as fully as possible.
2. Regulator inlet (upstream) pressure too high.
Possible Causes
Remedies
A. Regulator undersized.
A1. Confirm by opening bypass valve together with regulator.
A2. Check actual flow conditions, resize regulator; if regulator has
inadequate capacity, replace with larger unit.
B. Plugged inlet strainer.
B. Remove strainer screen and clean; consider leaving screen out.
C. Plugged trim.
C. Remove trim and check for plugged holes in cylinder.
D. Incorrect range spring (screwing out CCW of
adjusting screw does not allow bringing
pressure level to a stable and proper level).
D. Replace range spring with proper lower range. Contact factory.
E. Too much proportional band (rise).
E1. Review Proportional Band (rise) expected.
E2. Contact factory.
F. Restricted diaphragm movement.
F1. Ensure no moisture in spring chamber at temperatures below
freezing.
F2. Ensure no dust or debris entering vent opening. If rainwater or
debris can enter, re-orient spring chamber.
G. Diaphragm failure.
G. Replace diaphragm.
3. Main valve
fl
uid in loading
fl
uid piping.
Possible Causes
Remedies
A. Normal-life diaphragm failure.
A. Replace diaphragm.
B. Abnormal short-life diaphragm failure.
B1. Can be caused by excessive chattering. See No. 1 to remedy
chatter.
B2. Ensure not subjecting diaphragm to over-temperature conditions.
B3. Upstream (inlet) pressure buildup occurring that overstresses
diaphragms.
4. Sluggish operation.
Possible Causes
Remedies
A. Plugged piston guides.
A. Remove trim and clean.
B. Fluid too viscous.
B. Heat fluid. Contact factory.
C. Diaphragm failure.
C. Replace diaphragm.
5. Excessive seat leakage.
Possible Causes
Remedies
A. Foreign matter on seating surface.
A. Remove trim and clean.
B. Erosion/damage to seating surface.
B1. Relap seating surface.
B2. Replace cylinder sub-assembly and piston.
