520-202-000
9/03
Model S20 Non-Metallic Design Level 2 Page 25
Read these instructions
completely, before in-
stallation and start-up. It
is the responsibility of
the purchaser to retain
this manual for reference. Failure to
comply with the recommendations stated
in this manual will damage the pump, and
void factory warranty.
IMPORTANT
PILOT VALVE SERVICING
To service the pilot valve first shut
off the compressed air supply, bleed the
pressure from the pump, and disconnect
the air supply line from the pump. Insert
the safety clip (item 1-N from Air
Distribution Valve assembly drawing)
into the smaller unthreaded holes in the
end cap (item 1-C from air distribution
valve assembly drawing).
Step #1:
See PUMP ASSEMBLY
DRAWING.
Using a
9
/
16
" wrench or socket,
remove the four capscrews (items 9)
and four flat washers (items 42). Remove
the air inlet cap (item 8) and air inlet
gasket (item 21). The pilot valve
assembly (item 2) can now be removed
for inspection or service.
Step #2:
Disassembly of the pilot
valve.
Remove the pilot valve spool (item
2-F). Wipe clean, and inspect for dirt,
scratches or wear. Replace the spool if
necessary.
Remove the two retaining rings
(items 2-C) from each end of the pilot
valve body using clip ring pilers.
Remove the two pilot valve bushings
(items 2-B), five spacers (items 2-D),
and six spool wipers (items 2-E) by
pushing gently from other end of the
pilot valve body. Inspect the wipers for
cuts and/or wear. Replace any wipers
as necessary.
Step #3:
Re-assembly of the pilot
valve.
First install a spiral retaining ring to
one end of the pilot valve body. Install
one bushing making sure the step side
faces toward the wiper. Apply a light
coating of grease to the outside
diameter of each wiper. Next, gently push
in the wipers and spacers until they are
against the installed retaining ring in the
opposite end of the pilot valve body.
Install the remaining bushing making
sure the step side faces the wiper. Install
the remaining retaining ring using clip ring
pilers.
Apply a light coating of grease to the
inner diameter of each wiper. Also apply
a light coating of grease to the outer
diameter of the pilot valve spool and
gently push the spool through each wiper.
Step #4:
Inspect the actuator
plungers.
See PUMP ASSEMBLY DRAWING.
The actuator plungers (items 31) can
be reached through the stem cavity of
the pilot valve in the intermediate
assembly (item 4).
Remove the plungers (items 31) from
the bushings (item 7) in each end of the
cavity. Inspect the installed o-ring (items
28) for cuts and/or wear. Replace the o-
rings if necessary. Apply a light coating
of grease to each o-ring and re-install
the plungers in to the bushings. Push
the plungers in as far as they will go.
Step #5:
Re-install the pilot valve
ssembly into the intermediate assembly.
Be careful to align the ends of the
stem between the plungers when
inserting the stem of the pilot valve into
the cavity of the intermediate.
Re-install the gasket (item 21), air
inlet cap (item 8), capscrews and
washers (items 9 and 42).
Connect the air supply to the pump.
Remove the safety clip (item 1-N) from
the end cap (item 1-C). The pump is now
ready for operation.
Summary of Contents for S20
Page 2: ......
