Cashco 3500 - Manual (Page 4)

4 IOM-3500
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 Dis-assemble: Remove cover bolts (22), cover
(2) and cover gasket (12).
Inspect cover for corrosion, damage, or product
build up. Clean with a suitable solvent, replace as
necessary.
NOTE: During re-assembly, install new cover
gaskets (12) (5/32-inch diameter Gortex rope joint
sealant). For FRP material - bolting (22) for cover
(2) should be tightened to 50 in. - lbs. (5.6 Nm).
Remove pallet assembly, including any loading
weights (18) that may be on the pallet (4).
Clean and inspect pallet (4) assembly. Inspect the
diaphragm (5) and replace if necessary.
To Replace Diaphragm: Place stem (10) 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 (6) 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 (6), washer (24), lock-washer (19) and tighten
nut (23) on stem. Insert cotter pin (61) through hole
in stem and secure.
Inspect and clean 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 (16), spacers
(69) (Use fl ats on the guides and rotate CCW.) Mark
the location of the guides and spacers on the seat
ring (3) for reference at re-assembly.
Lift up to remove seat ring (3) and gasket (13).
Inspect guides (16) 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 gaskets and
install in body (1).
To Remove Lower Gasket: Separate pipeaway
body (20) from spool piece (25). Remove lower
gasket (13) and clean sealing surfaces of both parts.
Apply TFE paste to both sides of new gasket (13)
and install on spool piece (25).
Re-assemble vent in reverse order, making sure
that the pallet and loading weights are in their proper
location. Tighten bolts (11) and guides (16) to 15 ft.
lbs. (20.3 Nm). When installing the cover, ensure the
stem (10) is inserted in the stem guide.
WARNING
When assembling the vent, ensure that the stem is
straight and fi ts into the guide in the cover.
If the stem is cocked at an angle, pallet lift may be com-
pletely blocked . This can cause a tank failure, severe
personal injury and material damage.
SECTION V
CAUTION
The pipeaway body (20) is no longer fastened securely
to the spool piece (25) and could fall and cause severe
personal injury and material damage.