Cashco DA1 - Manual (Page 5)

5 IOM-DA1
13. Evenly loosen the three cage cap screws
(18) in single revolution increments. If the
reg u la tor con tains a lower piston spring (22),
the ITA should rise as the cage cap screws
(18) are evenly backed out. A downwards
holding force should be ap plied to the top of
the piston-guide bearing (13) to pre vent the
ITA from pop ping up as the last threads of the
cage cap screws (18) are backed out.
14. Remove the ITA by pulling up on the valve
plug (20). Set ITA aside.
15. Remove the lower piston spring (22), as
applicable, from within the body (23). NOTE:
Com po si tion diaphragm constructions do not
nor mal ly include a lower piston spring (22); all
metal diaphragm constructions MUST in clude
a lower piston spring (22).
16. Remove o-ring cage seal (15).
17. If supplied, remove internal sensing drilled
plug (32) using 5/32" (4 mm) Allen wrench.
18. Remove body (23) from vise. Clean all reus-
able metal parts according to owner's pro ce-
dures. NOTE: On regulators originally suplied
as Special Cleaning Option-55, -56, or -57,
maintenance must include a level of clean li-
ness equal to Cashco cleaning standards of
#S-1134, #S-1542, #S-1589 respectively.
Con tact factory for details.
C. Disassembly of the ITA:
B. Main Valve Disassembly:
WARNING 1
SYSTEM UNDER PRESSURE. Prior to per form-
ing any maintenance, isolate the reg u la tor from
the sys tem and relieve all pressure. Failure to
do so could result in personal injury.
1. Shut down the system in accordance with
Section VI.
2. Disconnect the external sensing line, if
installed.
3. Though it is possible to disassemble the valve
unit while installed in a pipeline, it is recom-
mended that maintenance be done in a shop
when possible. The description thereafter will
assume shop disassembly. Remove valve
from pipeline.
4. Place the valve unit in a vise with the spring
chamber (4) upwards.
5. Loosen adjusting screw lock nut (2) and relax
range spring (6) forces by turning adjusting
screw (1) CCW (viewed from above) until
removed from spring chamber (4).
6. Loosen the diaphragm fl ange bolts (11) and
nuts (12) uniformly.
7. Place matchmarks on body (23) and spring
chamber (4) fl anges. Remove the spring
chamber (4).
8. Remove spring follower (5) and range spring
(6).
9. For composition diaphragm construction,
hold the milled “fl ats” on top of the valve plug
(20) stationary with vise grips. Loosen and
remove the diaphragm lock nut (7). NOTE:
Metal diaphragm constructions do NOT have
a diaphragm lock nut (7).
10. Remove upper diaphragm pressure plate
(8).
11. Remove diaphragm(s) (9, 9.1, 9.2, 9.9) and
o-ring upper stem seal (14.1). Examine
diaphragm(s) to determine whether failed; de-
termine if op er at ing conditions are exceeding
pressure, pressure drop or temperature limits.
12. For composition diaphragm construction,
remove lower diaphragm pusher plate (10).
Figure 2: Assembled ITA,
Composition Di a phragm Construction
1. Units with Composition Diaphragm(s) (See
Figure 2):
a. Pull the valve plug (20) down wards and
out of the piston-guide bear ing (13) and
out of the cage's (19) bottom, while hold-
ing the cage (19).
b. Remove the piston-guide bearing (13)
20
14.2
14.3
13
27
15
16
17
19
21
20