Cashco 3381 - Manual (Page 5)

IOM-3381/4381 5
4. Clean fl at mating surfaces of body (1) to body
cap (6) shoulder. Be careful not to scratch
either surface.
5. Clean debris from within the body (1) cav-
ity. Parts to be reused should be cleaned
ac cord ing to own er's pro ce dures. NOTE:
On regulators orig i nal ly sup plied as “ox y gen
clean”, Options 3381-5 & -55, 4381-36 & 55
main te nance must in clude a level of clean li-
ness equal to Cashco's clean ing stan dard
#S-1134. For regulators orig i nal ly sup plied
as “cleaned for Phar ma ceu ti cal and Food ap-
pli ca tions” Op tions 4381-37 and 4381-37S,
main te nance must include a level of clean li-
ness equal to Cashco cleaning stan dard #S-
1576. Con tact factory for details.
6. If supplied with Opt-4 Stabilizer, install new
stabilizer seal (30) properly oriented onto
piston (16).
7. Slide the piston (16), including stabilizer seal
(30) if supplied, slowly into the body cavity.
Use thumbs to ease stabilizer seal(30) into
the body cavity.
8. Place piston spring (7) over spring hub of the
piston (16).
9. Apply pipe thread sealant to the body cap (6)
threads. Screw body cap (6) into body (1).
When body cap is fully down against body
(1) at the body cap (6) shoulder, impact the
body cap (6) into the body (1). NOTE: When
unit is put into service and pressurized, these
two parts seal metal-to-metal with no gasket.
10. Bench test unit for suitable operation. NOTE:
Regulators are not tight shutoff devices.
Even if pressure builds up beyond set point,
a reg u la tor may or may not develop bubble
tight shutoff. In general, tighter shutoff can
be expected with composition seat.
11. Pressurize with air and spray liquid leak de-
tec tor to test around body cap (6) and body
(1) for leak age. Test pres sure should be a
mini mum of 100 psig (6.9 Barg) at the inlet.
2. Regulator can't pass suffi cient fl ow.
VII. TROUBLE SHOOTING GUIDE
1. Erratic operation; chattering.
SECTION VII
Possible Causes Remedies
A. Oversized regulator; inadequate rangeability. A1.
A2.
A3.
A4.
A5.
Check actual fl ow conditions, re-size regulator for minimum and maximum fl ow.
Increase fl ow rate.
Decrease regulator pressure drop; decrease inlet pressure by placing a throttling orifi ce
in inlet piping union.
Install next step higher range spring. Contact factory.
Before replacing regulator, contact factory.
B. Worn piston; inadequate guiding. B. Replace trim ( possible body replacement).
C. Weakened/broken piston spring. C. Replace piston spring. De ter mine if corrosion is causing the failure.
Possible Causes Remedies
A. Regulator undersized. A1.
A2. Confi rm by opening bypass valve together with regulator.
Check actual fl ow conditions, re-size regulator; if regulator has inadequate capacity,
replace with larger unit.
B. Incorrect range spring (screwing in CW of ad-
justing screw does not allow bringing pressure
level up to proper level). B. Replace range spring with proper higher range. Contact factory.
C. Too much droop. C1.
C2. Review droop expected.
Contact factory.
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.
B2.
B3.
B4. Can be caused by excessive chattering. See No. 1. to remedy chatter.
Can be caused by corrosive action. Consider alternate diaphragm material.
For composition diaphragms, ensure not subjecting to over-temperature conditions.
Downstream (outlet) pressure buildup occurring that overstresses diaphragms. Relo-
cate regulator or protect with safety relief valve.