Owner's manual

IOM-DA6 1

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.