Cashco 1000 HP Basic - Manual (Page 9)

9 IOM-1000HP-Basic
2. Regulator outlet (downstream) pressure too low.
Possible Causes Remedies
A. Setpoint too low. A. Turn adjusting screw down (CW) to increase setpoint.
B. Regulator undersized. B1. Confi rm by opening bypass valve together with regulator.
B2. Check actual fl ow conditions, resize; if regulator has inadequate capacity,
replace with larger unit.
C. Plugged inlet strainer. C. Remove strainer screen and clean; consider leaving screen out.
D. Plugged trim. D. Remove trim and check for plugged holes in piston, or debris in guide
zone or jet zone.
E. Incorrect range spring (turning adjusting
screw CW does not allow bringing pressure
level up to proper level).
E. Replace range spring with proper higher range. Contact factory.
F. Too much droop. F1. Review droop expected. (See 2.B1 above.)
F2. Diaphragm setting too low; check setting and raise as required.
F3. Consider composition diaphragm over metal.
F4. Improper jet; make sure jet matches actual fl uid.
G. Restricted diaphragm movement (pressure
plate hitting upstops)
G1. Diaphragm setting too high; check and lower as required.
G2. 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.
H. Restricted diaphragm movement
(overstretched
diaphragm).
H1. Diaphragm setting too low; check and increase as required.
H2. 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 occurring that overstresses diaphragms.
C. Pusher plate gasket leaking. C. Replace gasket.
D. Improper (oversized) jet. D. Replace existing piston with new piston with proper jet.
E. Plugged trim. E. Remove trim and check for plugged holes in piston, or debris in guide
zone or jet zone.
4. Excessive pressure downstream.
Possible Causes Remedies
A. Regulator not closing tightly. A1. Overly compressed range spring; i.e. approaching solid height. Use next
higher range spring.
A2. Inspect the seating. Clean and lap metal seat surfaces; replace if lapping
does not remedy. If composition seats are depressed, nicked or embedded
with debris, replace seat disc.
A3. Diaphragm setting too high; check setting.
A4. Inlet pressure too high for orifi ce size; check permissible inlet (P
1
) pressure
level for a given outlet. Change to reduced port if required.
A5. Leakage past pressed in valve seat ring; consider integral seat.
A6. When diaphragm sub-assembly was put into place, the rocker arm got
between the stud collar and the stud nut rather than on top of the stud collar.
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. D1. Diaphragm setting too high; check and lower as required.
D2. 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.