Cashco HP - Manual (Page 5)

IOM-HP 5
SECTION VII
VII. TROUBLE SHOOTING GUIDE
1. Erratic operation; chattering.
Possible Causes Remedies
A. Oversized regulator; inadequate rangeability. A1. Check actual fl ow conditions, resize regulator for minimum and maximum fl ow.
A2. Increase fl ow rate.
A3. Decrease regulator pressure drop; decrease inlet pressure by placing a throttling
orifi ce in inlet piping union.
A4. Install next step higher range spring. Contact factory.
A5. Before replacing regulator, contact factory.
B. Worn piston, inadequate guiding B. Replace trim.
C. Weakened/broken piston spring. C. Replace piston spring. Determine if corrosion is causing the failure; if so, then consider
NACE acceptable trims.
2. Downstream pressure will not reach desired setting.
Possible Causes Remedies
A. Regulator undersized. A1. Confi 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.
A3. Decrease regulator pressure drop; decrease inlet pressure by placing a throttling
orifi ce in inlet piping union.
A4. Install next step higher range spring. Contact factory.
A5. Before replacing regulator, contact factory.
B. Plugged trim. B. Remove trim and check for plugged holes in cylinder.
C. Incorrect range spring (screwing in CW of
adjusting screw does not allow bringing
pressure level up to proper level).
C. Replace range spring with proper higher range. Contact factory.
D. Too much proportional band (droop). D1. Review P.B. (droop) expected.
D2. Contact factory.
E. Restricted diaphragm movement. E. 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, reorient spring
chamber.
3. Leakage through the spring chamber vent hole.
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. Can be caused by corrosive action. Consider alternate diaphragm material.
B3. For composition diaphragms, ensure not subjecting to over-temperature conditions.
B4. Downstream (outlet) pressure buildup occuring that overstresses diaphragms. Relocate
regulator or protect with safety relief valve.
4. Excessive pressure downstream.
Possible Causes Remedies
A. Regulator not closing tightly. A1. Inspect the seating. Clean and lap metal seat surfaces; replace if lapping does not reme-
dy. If composition seats are depressed, nicked or embedded with debris, replace trim.
A2. Inspect guides in body cap (balanced trim). If damaged, replace body cap and/or
piston.
B. Downstream block. B. Check system; isolate (block) fl ow at regulator inlet - not outlet. Relocate regulator if
necessary.
C. No pressure relief protection. C. Install safety relief valve, or rupture disc.
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 regula-
tor.