Cashco 1000 HP Differential - Manual (Page 10)

10 IOM-1000HP-Dif fer en tial
2. Regulator differential pressure too low.
Possible Causes Remedies
A. Setpoint too low. A. Turn adjusting screw down (CW) to increase
setpoint.
B. Regulator undersized; outlet pressure B1. Confi rm by opening bypass valve together with
(P
2
) droops below loading pressure regulator.
(P
Load
). B2. Check actual fl ow conditions, resize reg u la tor;
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 E. Replace range spring with proper higher range.
screw CW does not allow bringing pressure Contact factory.
level up to proper level).
F. Too much proportional band (droop); F1. Re view P.B. (droop) expected. (See 2.B1 above.)
outlet pressure (P
2
) droops below loading F2. Diaphragm setting too low; check setting and
pressure (P
Load
). raise as required.
F3. Consider composition diaphragm over metal.
F4. Improper jet; make sure jet matches actual fl uid.
G. Restricted diaphragm movement. (Pressure G. Diaphragm setting too low; check and raise
plate hitting downstops.) as required.
3. Leakage through the body spacer vent hole, or mixing of fl uids.
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 valve chatter.
B2. Can be caused by corrosive action. Consider
alternate diaphragm material.
B3. For composition diaphragms, ensure not subject-
ing to over-temperature conditions.
B4. Downstream (outlet) pressure buildup occuring
that overstresses diaphragms.
B5. Shutoff of valve inlet pressure while loading
pressure is still on.
C. Pusher plate gasket or O-Ring leaking. C. Replace gasket and O-ring.