Cashco DA6 User Manual
Page 13
IOM-DA6
13
4. Diaphragm continually breaks (steam service regulators).
Possible Causes
Remedies
A. Stem seals (14) which protect
A. Replace with new stem seals (14).
fl uorocarbon elastomer in diaphragm
assembly may have deteriorated.
B. Diaphragm nut (7) may not be
B. Confi rm torque value in accordance with Section VII,
torqued to proper value.
paragraph E-13.
C. Diaphragm too stiff causing it
C. Follow proper preforming and air evacuation techniques
to crack in service.
during diaphragm installation in accordance with Section VII,
paragraph
F-10.
5. Diaphragm continually breaks (all regulators).
Possible Causes
Remedies
A. Differential pressure across dia-
A1. Be aware of limits as well as where the various pressures
phragm may have exceeded limits.
are acting. Install pressure safety equipment as necessary.
(See Table 1 in Tech Bulletin
A2. Consider if full diaphragm support, Opt-81, should be added.
DA6-TB.)
6. Leakage at diaphragm fl ange.
Possible Causes
Remedies
A. Body bolts not torqued properly.
A. Torque to proper value (see Section VII, paragraph F-11).
B. Pressures at diaphragm may be
B. Consult factory.
too high for regulator design.
7. Leakage across seat.
Possible Causes
Remedies
A. Contamination (debris) in regulator.
A. Remove internals, clean, and if necessary, replace
sealing and seating elements. *
B. Oversized regulator; valve plug
B. Check actual fl ow conditions; resize regulator for minimum
operates directly next to seat.
and maximum fl ow; if necessary, replace with smaller
regulator.
* Excess seat leakage may be diagnosed when a failure of the dynamic side seal has occurred. Inspect both
potential internal leak paths.