SANDPIPER EB1-SM - Manual (Page 4)

Model EB1-SM Type 3 Page 4 520-079-000 9/00
CAUTION
When removing capscrews on
suction or discharge valve retainer/
cap, make sure all pressure on
suction and discharge side of pump
has been relieved. Re-lock safety
wire on the capscrews before
continuing use.
Torquing the air inlet capscrews
Pilot valve removal
Pilot valve spool and o-rings
Bushings and o-rings
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, without shearing the o-
rings. Re-install the spool, opposite end cap and retaining ring on the valve body. After
inspecting and cleaning the gasket surfaces on the valve body and intermediate, re-install 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
The pilot valve assembly is accessed by removing the main air distribution valve body from
the pump and lifting the pilot valve body out of the intermediate housing.
Most problems with the pilot valve can be corrected by replacing the o-rings. Always
grease the spool prior to inserting it into the sleeve. If the sleeve is removed from the
body, reinsertion must be at the chamfered side. Grease the o-rings to slide the sleeve
into the valve body. Securely insert the retaining ring around the sleeve. When
reinserting the pilot valve, push both plungers (located inside the intermediate bracket)
out of the path of the pilot valve spool ends to avoid damage.
PILOT VALVE ACTUATOR
Bushings for the pilot valve actuators are held in the inner chambers wth retaining
rings. An o-ring is behind each bushing. If the plunger has any sideways motion check
o-rings and bushings for deterioration/wear. The plunger may be removed for inspection
or replacement. First remove the air distribution valve body and the pilot valve body from
the pump. The plungers can be located by looking into the intermediate. It may be
necessary to use a fine piece of wire to pull them out. The bushing can be turned out
through the inner chamber by removing the outer chamber assembly. Replace the
bushings if pins have bent.
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 movement of diaphragm.
2. Pump cycles but will not pump
A. Suction side of pump pulling in air. Check the suction line for air leaks and be sure
that the end of the suction line is submerged. Check flange bolting. Check valve flanges
and manifold to chamber flange joints.