Cashco 3200 - Manual (Page 4)

4 IOM-3200
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), covers
(2) and cover gaskets (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 covers
(2) should be tightened to 50 in. - lbs. (5.6 Nm).
Remove pressure and vacuum pallet assemblies,
including any loading weights (18) that may be on
the pallets (4). NOTE: As the pallets are removed
from the vent, identify each assembly (including the
stack of weights) by tagging as “pressure” side or
“vacuum” side.
Clean and inspect pallet (4) assemblies. Inspect the
diaphragms (5) and replace if necessary.
To Replace Diaphragms: Place stems (9,10) 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 (6,28) and
diaphragms (5). NOTE: Apply TFE paste to threads
of the stem and around hole on the pallets (4).
Install new diaphragms (5). Re-install diaphragm
plate (6,28), washer (24), lock-washer (19) and
tighten nut (23) on stem. Insert cotter pin (61)
through hole in stem and secure.
Inspect and clean pressure / vacuum seat ring(s)
(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 Rings/Gaskets: Rotate bolts
(11) CCW and remove. Remove guides (8)(16)
and spacers (69) (Use slot on top of guides and
rotate CCW.) Mark the location of these items on
the appropriate seat ring (3) for reference at re-
assembly.
Lift up to remove seat rings (3) and gaskets (13).
Inspect guides (8)(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 body (1). Remove lower gasket (13)
and clean sealing surfaces of both parts. Apply TFE
paste to both sides of new gasket (13) and install in
body (1).
Re-assemble vent in reverse order, making sure
that the pressure and vacuum pallet(s) and loading
weights are in their proper location. Tighten bolts
(11), guides (8)(16) to 15 ft. lbs. (20.3 Nm). When
installing the covers, ensure the pressure stem
(10) and vacuum stem (9) are inserted in the stem
guides.
To Remove Inlet Screen: Rotate bolts (15) CCW
and remove. Inspect and clean screen (14) and
reinstall to body (1).
WARNING
When assembling a P/V vent, always put the
p r e s s u r e ( l o n g s t e m ) a n d v a c u u m ( s h o r t
stem) pallet assemblies back in their original
location and ensure that the stem is straight and fi ts
into the guide in the cover or weatherhood.
If the pressure and vacuum pallet assemblies are mixed
at assembly, the settings will be changed and the fl ow
for the vacuum side will be restricted.
If the stem is cocked at an angle, pallet lift may be com-
pletely blocked. An over-pressure can occur if any of
these three conditions happens. 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 body (1) and could fall and cause severe per-
sonal injury and material damage.