520-202-000
9/03
Model S20 Non-Metallic Design Level 2 Page 29
Modular Check Valve Drawing
MODULAR CHECK VALVE
SERVICING
Before servicing the check valves,
first shut off the suction line and then
the discharge line to the pump. Next, shut
off the compressed air supply, bleed air
pressure from the pump, and disconnect
the air supply line from the pump. Drain
any remaining fluid from the pump. The
pump can now be removed for service.
To access the modular check valve,
remove the elbows (items 20 from pump
composite repair parts drawing). Use a
9
/
16
" wrench or socket to remove the
fasteners. Once the elbows are removed,
the modular check valves can be seen
in the cavities of the outer chamber
(items 17).
Next remove the check valve seal
(item 37). Inspect the seal for cuts or
pinched areas. Replace seal as needed.
Disassemble the component parts of
each modular check valve. Inspect the
check valve retainer (item 32) for cuts,
abrasive wear, or embedded materials.
Replace as needed.
Inspect the check balls (items 3) for
wear, abrasion, or cuts on the spherical
surface. The check valve seats (items
38) should be inspected for cuts,
abrasive wear, or embedded material on
the surfaces of both the external and
internal chamfers. The spherical surface
of the check balls must seat flush to
the surface of the inner chamfer on the
check valve seats for the pump to
operate to peak efficiency. Replace any
worn or damaged parts as necessary.
Remove the remaining check valve
seal (item 37). Inspect the seal for cuts
or pinched areas. Replace seal as
needed.
Re-assemble the modular check
valve. The seat should fit snugly into the
retainer.
Place a check valve seal (item 37)
into the cavity of the outer chamber (item
17). Make sure the chamfer side of the
seal faces out. Insert the modular check
valve into the outer chamber with the
retainer facing up. Install a check valve
seal (item 37). Make sure the chamfer
side of the seal faces the chamfer on
the check valve seat or retainer.
The pump can now reassembled,
reconnected and returned to operation.
Summary of Contents for S20
Page 2: ......
