SANDPIPER ET2 - M - Manual (Page 7)

Model ET2-M Type 1 Page 6 et2dl2sm-0614
CHECK VALVE SERVICING
Need for inspection or service is usually indicated by poor priming, unstable cy-
cling, reduced performance or the pump’s cycling but not pumping.
Remove the six flange bolts securing the inlet and outlet flanges to the manifold.
Inspect the surfaces of both check valve and seat for wear or damage that could
prevent proper sealing. If pump is to prime properly, valves must seat air tight (see
Fig. 6).
DIAPHRAGM SERVICING
Driver Diaphragms:
Drain the driver diaphragm chamber by removing the boss plug on the underside
of the driver chamber. NOTE: This is also the part used for leak detector probes.
Remove twelve bolts securing the two manifolds to the chambers. Remove eight bolts
securing the diaphragm chamber. This permits inspection of the TFE diaphragm and
the driver diaphragm. Loosen the plate which secures the diaphragm and plate to the
rod by keeping the diaphragm engaged with the inner diaphragm chamber. Insert two
or three capscrews through the bolt holes so the diaphragm cannot rotate when loos-
ening. The diaphragm plates, diaphragm and bumper will now come off the assembly.
Repeat all actions if the other diaphragm needs to be inspected or replaced.
NOTE: See “Filling of Driver Chamber with Liquid” for the correct procedure to
recharge the pump for operation.
Reassembly is the reverse of the tear down. During reassembly, be sure the rub-
ber bumper is on the rod on each side. Install the diaphragm with the natural bulge to
the outside as marked on the diaphragm. Be sure that the large radius side of each
plate is toward the diaphragm. Place the sealing washer between the inner diaphragm
plate and the end of the rod. Tighten the plate to approximately 25 ft. lbs. (3.456
pounds/sq. cm.). Torque while allowing the diaphragm to turn freely with the plate.
Hold the opposite side with a wrench on the plate to prevent rotation of the rod. If the
opposite chamber is assembled, this will not be necessary.
When reassembling the outer chambers and the manifold, the bolts securing the
manifold flange to the chamber should be snugged prior to tightening the mani-
fold flange. Finish tightening the manifold flange bolts after the chamber bolting is
secured.
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
(see Fig. 9).
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 with
retaining rings. An o-ring is behind each bushing. If the plunger has any sideways
motion check o-rings and bushings for deterioration or 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 intermedi-