5
IOM-8311HP/LP
A. Plugged spring chamber vent.
A. Clean vent opening.
B Fluid too viscous.
B. Heat
fl
uid. Contact factory.
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. Can be caused by corrosive action. Consider alternate diaphragm material.
B3. For composition diaphragms, ensure not subjecting to over-temperature
conditions.
B4. Upstream (inlet) pressure buildup occuring that overstresses dia-
phragms. Relocate regulator or protect with safety relief valve.
A.
Regulator
undersized.
A1.
Con
fi
rm by opening bypass valve together with regulator.
A2.
Check
actual
fl
ow conditions, resize regulator; if regulator has inadequate
capacity, replace with larger unit.
B. Incorrect range spring (screwing out CCW of
B. Replace range spring with proper lower range. Contact factory.
adjusting screw does not allow bringing pressure
to a stable and proper level).
C. Too much build.
C1. Review build expected.
C2.
Contact
factory.
D. Restricted diaphragm movement.
D. Ensure no moisture in spring chamber at temperatures below freeze point.
Ensure no dust or debris entering vent opening. If rainwater or debris can
enter, re-orient spring chamber.
Remedies
Possible Causes
Remedies
Possible Causes
Remedies
Possible Causes
A. Oversized regulator; inadequate rangeability.
A1. Check actual
fl
ow conditions, resize regulator for minimum and maximum
fl
ow.
A2. Decrease regulator pressure drop; decrease inlet pressure by placing a
throttling
ori
fi
ce in inlet piping union.
A3. Install next step higher range spring. Contact factory.
A4. Before replacing regulator, contact factory.
B. Worn plug/stem assembly; inadequate guiding.
B1. Contact factory.
Remedies
Possible Causes
2. Leakage through the spring chamber vent hole.
3. Upstream pressure too high.
4. Sluggish operation.
SECTION VII
VII. TROUBLE SHOOTING GUIDE
1. Erratic operation; chattering.
