SANDPIPER EB3-SM - Manual (Page 4)

Model EB3-SM Page 4 520-057-000 8/00
is made by removing a retaining ring (each end) securing the end cap on the valve
body assembly. With the end caps removed, slide the spool back and forth in the
sleeve. The spool is closely sized to the sleeve and must move freely to allow for
proper pump operation. An accumulation of oil, dirt or other contaminants from the
pump’s air supply, or from a failed diaphragm, may prevent the spool from moving
freely. This can cause the spool to stick in a position that prevents the pump from
operating. If this is the case, the sleeve and spool set should be removed from the
valve body for cleaning and further inspection.
Remove the spool from the sleeve. Using an arbor press or bench vise (with an
improvised mandrel), press the sleeve from the valve body. Take care not to damage
the sleeve. At this point, inspect the o-rings on the sleeve for nicks, tears or abrasions.
Damage of this sort could happen during assembly or servicing. A sheared or cut o-
ring can allow the pump’s compressed air supply to leak or bypass within the air valve
assembly, causing the pump to leak compressed air from the pump air exhaust or not
cycle properly. This is most noticeable at pump dead head or high discharge pressure
conditions. Replace any of these o-rings as required or set up a routine, preventive
maintenance schedule to do so on a regular basis. This practice should include
cleaning the spool and sleeve components with a safety solvent or equivalent,
inspecting for signs of wear or damage, and replacing worn components.
To re-install the sleeve and spool set, lightly lubricate the o-rings on the sleeve with
an o-ring assembly lubricant or lightweight oil such as 10 wt. air line lubricant). Re-
install one end cap, and retaining ring on the valve body. Using the arbor press or
bench vise that was used in disassembly, carefully press the sleeve back into the valve
body. Re-install the spool, opposite end cap and retaining ring on the valve body,
without shearing the o-rings. After inspecting and cleaning the gasket surfaces on the
valve body and intermediate, reinstall the valve body on the pump using new gaskets.
Tighten the four hex head capscrews evenly and in an alternating cross pattern, at 150
in./lbs. (16.94 Newton meters).
PILOT VALVE SERVICING
This assembly is reached by removing the air distribution valve body from the
pump and lifting the pilot valve body out of the intermediate housing.
When reinserting an externally serviceable pilot valve, push both plungers out of
the path of the pilot valve so that they and the pilot valve are not damaged.
Service Note: If a problem arises with the pilot valve, it is usually corrected by
replacing only o-rings. Always grease the spool prior to inserting into the sleeve. If the
sleeve is removed from the body, reinsertion must be from the same side it was
removed from, the chamfered side. Again, grease the o-rings so that it slides into the
body. Make sure the retaining ring has securely been inserted around the sleeve.
PILOT VALVE ACTUATOR SERVICING
The bushings for the pilot valve actuators are threaded into the intermediate
bracket from the outside. The plunger may be removed for inspection or replacement
from the inside by removing the air distribution valve body and the pilot valve body from
the pump. The plungers should be visible as you look down into the intermediate from
the top. Depending on their position, it may be necessary to use a fine piece of wire
to pull them out.
Under rare circumstances, it may become necessary to replace the o-ring seal.
The bushing can be turned out through the inner chamber by removing the outer
chamber assembly to reach the bushing.
TROUBLESHOOTING
1. Pump will not cycle
A. Check to make sure the unit has enough pressure to operate and that the air inlet
valve is open.
B. Check the discharge line to insure that the discharge line is neither closed nor
blocked.
C. If the spool in the air distribution valve is not shifting, check the main spool. It must
slide freely.
D. Excessive air leakage in the pump can prevent cycling. This condition will be
evident. Air leakage into the discharge line indicates a ruptured diaphragm. Air
leakage from the exhaust port indicates leakage in the air distribution valve. See
further service instructions.
E. Blockage in the liquid chamber can impede movements of diaphragm.
IMPORTANT
This pump is pressurized internally with
air pressure during operation. Always
make certain that all bolting is in good
condition and that all of the correct
bolting is reinstalled during assembly.
HAZARD WARNING
POSSIBLE EXPLOSION HAZARD can
result if 1, 1, 1-Trichloroethane, Methyl-
ene Chloride or other Halogenated
Hydrocarbon solvents are used in
pressurized fluid systems having
Aluminum or Galvanized wetted parts.
Death, serious bodily injury and/or
property damage could result. Consult
with the factory if you have questions
concerning Halogenated Hydrocarbon
solvents.