Cashco 5500 - Manual (Page 6)

6 IOM-5500
SECTION VII
VII. VENT VALVE MAINTENANCE:
A. General:
1. The Model 5500 POVV does not require
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should be checked periodically, at least
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functioning properly and that the set point
is correct.
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failsafe manner. The failure of a seal or a
diaphragm will cause pressure to be vent-
ed out through a pipeaway connection VJG
resulting loss in pressure will cause the
main valve to open under rising pressure.
3. Periodic inspection for seat tightness
should be done to ensure compliance with
local air pollution control requirements. If
the vent relieves to the atmosphere, this
maybe accomplished with a gas detector
calibrated for the principle product in the
system.
4. The vent valve will need to be removed
from the tank for inspection of diaphragms,
gaskets and seals. When this is done, the
vent must be handled carefully using the
lifting lugs and the body.
5. The main and pilot valve housings, bodies,
pallet assemblies and other components
are exposed to the process vapor.
B. Disassembly:
1. Disconnect the tubing connections (pilot to
main Valve) (48, 57 and ) and remove
the pilot by rotating the pilot body () as-
sembly CCW from nipple (53).
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a. Paint or embed a match mark between
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b. Loosen and remove nuts (35), lock
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screw (34).
c. Lift up and remove the upper case (33)
assemby and set aside.
d. Remove diaphragm (41) and replace
with new diaphragm. Position and align
bolt holes in the circumference of the dia-
phragm with the holes in the lower case
 
e. Reposition upper case assy (33) on di-
aphrgm (41). Align marks of a. above.
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(36), lock washer (37) and nuts (35) and
tighten.
g. Install pilot body assembly on nipple
(53) tight with CW rotation. Ensure straight
connector () of the pilot valve assembly
is directly above sensing tube connector
(48) of the main valve assembly.
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(48),(). Refer to Section IX for Calibra-
tion and Testing.
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a. Paint or embed a match mark between
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area.
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move. Grasp the lower and upper case
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c. Lay the whole upper case assembly
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assembly up.
CAUTION
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