SANDPIPER DMF2S - Manual (Page 11)

dmf2dl5sm-rev0614 Model DMF2 Page 9
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 threaded into the intermediate
bracket from the outside. 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.
WARRANTY
This unit is guaranteed for a period of five years against defective material
and workmanship.
PROBLEM
Pump cycles but will not pump. (Note: higher suction lifts require faster cycling speed for priming.)
POSSIBLE CAUSES:
A. Air leak in suction line.
B. Excessive suction lift.
C. Flap valve not seating properly.
D. Leakage at joint of suction manifold or elbow flange.
E. Suction line or strainer plugged.
F. Diaphragm ruptured.
PROBLEM
Pump will not cycle. (Note: Always disconnect air supply to relieve air pressure before disassembling any
portion of pump.) POSSIBLE CAUSES:
A. Discharge hose or line plugged, or discharge head requirement greater than air supply pressure.
(Disconnect discharge line to check.)
B. Spool in air distribution valve not shifting. (Remove end cap and check spool — must slide freely.)
C. Diaphragm ruptured. (Air will escape out discharge line in this case.)
D. Blockage in diaphragm chamber preventing movement. (Shut off air supply and reopen after
pressure is relieved.)
PROBLEM
Uneven discharge flow. (Indicates one chamber not operating properly.)
POSSIBLE CAUSES:
A. Flap valve not sealing properly in one chamber.
B. Diaphragm failure in one chamber.
C. Air leak at suction manifold joint or elbow flange one side.
For additional information, see the Warren Rupp Troubleshooting Guide.
TROUBLESHOOTING - For additional information, see the Warren Rupp Troubleshooting Guide.