Cashco 3400 - Manual (Page 4)

4 IOM-3400
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 the weatherhood wing
nuts (7) and washers (72) and lift off weatherhood
(17) and bug screen (27).
Inspect weatherhood, and bug screen for corrosion,
damage, or product build up. Clean with a suitable
solvent, replace if necessary.
Remove pallet (4) assembly, including any loading
weights (18) that may be on the pallets (4).
Clean and inspect pallet assembly. Inspect the
diaphragm (5) and replace if necessary.
To Replace Diaphragms: 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 supports (16), spacers
(69) (Use fl ats on the supports and rotate CCW.)
Mark the location of supports on the seat ring (3) for
reference at re-assembly.
Lift up to remove seat ring (3) and gasket (13).
Inspect supports (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).
Re-assemble vent in reverse order, making sure
that the pallet and loading weights are in their proper
location. Tighten bolts (11) and supports (16) to 15
ft. lbs. (20.3 Nm). When installing the weatherhood,
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 weatherhood.
If the stem is cocked at an angle, pallet lift may be
completely blocked. An over-pressure can occur. This
can cause a tank failure, severe personal injury and
material damage.
SECTION V