JETStream 3000 series, Operation Manual, Page: 58 / 84

Operation Manual
50
Valve Inspection
1. Inspect all seals and discard as necessary.
2. Inspect the valve components. Discard exces-
sively pitted or otherwise damaged compo-
nents (Figure 90).
3. For valves with minor wear or corrosion, recon-
dition the valves as outlined in Valve Lapping.
Valve Lapping
Lapping is a polishing process in which two
surfaces are rubbed together with an abrasive
between them. Lapping the valves at regular
intervals ensures a tight fit between the valves
and valve seat for proper sealing. Regularly
lapping the valves allows the pump to operate
efficiently and helps increase valve life.
1. Disassemble the valve.
2. Apply lapping compound to the mating surface
on the suction valve (Figure 91).
3. Place the valve into position on the valve body.
Rotate the valve and valve body in opposite
directions with a light pressure for approxi-
mately 30 seconds.
4. Pause lapping momentarily by disengaging sur-
faces. Rotate the parts in the opposite direction
approximately 90 degrees. Do this a few times
during lapping. This will ensure that the lapping
compound distributes evenly along the valve
and valve seat interface.
Repeat for approximately 2-5 minutes, until an
even dull grey circular ring can be seen without
any remaining pits or surface imperfections.
5. Clean off the excess lapping compound with a
clean dry cloth. Inspect the contact surfaces for
uniform, dull gray sealing rings (Figure 92).
6. Continue the lapping process until the desired
sealing surface is achieved.
7. Repeat the lapping process for the discharge
valve.
8. When completed, clean all metal parts by sub-
merging in a mineral spirits solution for a few
minutes. Remove and air dry thoroughly with
compressed air. Ensure that no compound or
solution remains in the cross holes.
ATTENTION
Use silicon carbide lapping compound, 220 grit
medium fine.
Figure 90: Valve Pitting.
Excessive Pitting
Figure 91: Typical Example of Lapping Compound Application.
Lapping Compound
on Valve Seats
Figure 92: Properly Lapped Valve Seats.