Cashco 31-N - Manual (Page 7)

IOM-31-N 7
BODY SIZES 1/2', 3/4" & 1" (DN15, 20 & 25)
BODY SIZES 1-1/2" & 2" (DN40 & 50)
Figure 4
2. Remove lower casing (3) from body (1) as
de scribed in Section VI.C., Steps 1 and 2.
3. Remove both machine screws (22), wash-
ers (37) and retaining link age pivot pin (23).
(See Figure 8.) Lift link age lever (21) from
its position of en gage ment with stem (24)
bringing linkage pivot pin (23) along. Remove
pin (23) and inspect for wear, bend ing, etc.
Replace pin (23) if re quired.
4. Inspect linkage lever (21) for bending, dis tor-
tion, etc. Replace lever (21) if required.
5. Withdraw stem (24) through the neck of the
lower case. Inspect stem to assure that there
is no bend ing in the "slot" area where the
stem and linkage lever (21) engage. Replace
stem if there are any signs of bending or
friction in the stem guide or engagement
zones. NOTE: If regulator has external
sensing - replace the o-ring (44). Re-insert
stem back into lower casing.
6. Insert linkage pivot pin (23) thru hole in link-
age lever (21). Simultaneously engage the
linkage lever (21) and the stem (24), and
place pin (23) ends back into the “cradles”
of the pedestal supports of the lower casing
(3), replace washer (37), engage and tighten
both machine screws (22).
7. Reinstall diaphragm sub-assembly (DSA)
and spring chamber (4) as described in
Section VI.B., Steps 16 thru 23.
8. Reinstall actuator assembly (AA) to body (1)
as de scribed in Section VI.C., Steps 11 and
12.
E. Range Spring Replacement:
1. Remove closing cap (5) from spring chamber
(4).
2. Rotate adjustment screw (18) CCW to re-
mov al.
3. Remove existing range spring (17).
4. Install new range spring (17) (refer to Table
2).
5. Put thread locking compound on threads of
spring chamber (4) and on adjustment screw
(18).
6. Engage adjustment screw (18) into spring
cham ber (4) by rotating CW until the range
spring (17) begins to compress.
7. Shop calibrate the setpoint per Section VII.
8. Remove old nameplate (28) and drive screws
(29); install new nameplate with correct range
spring indicated.