Cashco 3300 - Manual (Page 4)

4 IOM-3300
V. MAINTENANCE
Tank or system protection is the primary function
of the weight loaded Pressure and/or Vacuum
Relief Vent. As a safety device, it is very important
that maintenance/inspection be done on a regular
interval. Maintenance should only be done by a
qualifi ed technician. Valve Concepts recommends
that all service be performed at the factory or a
factory authorized repair center. For information on
repair centers in your area, please contact factory.
To Disassemble: Remove cover bolts (22), covers
(2) and cover gaskets (12).
Inspect covers for corrosion, damage, or product
build up. Clean with a suitable solvent, replace as
necessary.
NOTE: Before reassembling covers, install new
cover gaskets (12) (5/32-inch diameter Gortex rope
joint sealant). For FRP material - bolting (22) for
covers (2) should be tightened to 50 in. - lbs. (5.6
Nm).
Remove pallet assembly (9), including any loading
weights (18) that may be on the pallet (4).
Clean and inspect pallet assembly. Inspect the
diaphragm (5) and replace if necessary.
To Replace Diaphragm: Place stem (9) in a vise
with threaded end up. Remove cotter pin (61), nut
(23), lock-washer (19) and washer (24).
Lift up to remove diaphragm plate (28) and
diaphragm (5). NOTE: Apply TFE paste to threads
of the stem and around hole on the pallet (4).
Install new diaphragm (5). Re-install diaphragm
plate (28), washer (24), lock-washer (19) and tighten
nut (23) on stem. Insert cotter pin (61) through hole
in stem and secure.
Inspect seat ring (3). Check seat surface for any
nicks, corrosion, pitting or product build up. Seat
surfaces must be clean and smooth for vent to
perform properly.
To Remove Seat Ring/Gasket: Rotate bolts (11)
CCW and remove. Remove guides (8), spacers
(69) (Use the slot on top of guides and rotate CCW.)
Mark the location of guides on the seat ring (3) for
reference at re-assembly.
Lift up to remove seat ring (3) and gasket (13).
Inspect guides (8) and inside of the body cavity
(1) for any corrosion or product build up. Clean if
necessary.
Apply TFE paste to both sides of new gasket and
install in body.
Re-assemble vent in reverse order, making sure that
the vacuum pallet and loading weights are in their
proper location. Tighten bolts (11), guides (8) and
spacers (69) to 15 ft. lbs. (20.3 Nm). When installing
the covers, ensure the stem (9) is inserted in the
stem guide.
To Remove Inlet Screen: Rotate bolts (15) CCW
and remove. Inspect and clean screen (14) and
reinstall to body (1).
WARNING
When assembling a vent, ensure that the stem
is straight and fits into the guide in the cover.
If the stem is cocked at an angle, pallet lift may be
completely blocked. This could result in an increase in
vacuum pressure in the tank and cause a tank failure,
severe personal injury and material damage.
SECTION V