Model MSB2 Page 4
msb2dl3sm-REV0317
REASSEMBLY
All procedures for reassembling the pump are the reverse of the previous
instructions with further instructions as shown:
1. The diaphragm assemblies are to be installed with the natural bulge outward or
toward the head of the center screw. Make sure both plates are installed with outer
radii against the diaphragm. After all components are in position in a vise and hand
tight, set a torque wrench for 480 inch pounds (40 ft. pounds) (54.23 Newton meters)
using a 1 1/16 (27mm) wrench or six pointed socket. After each diaphragm sub as-
sembly has been completed, thread one assembly into the shaft (held near the middle
in a vise having soft jaws to protect the finish) making sure the stainless steel washer
is in place on the capscrew.
Make sure 1/4"-20 mounting screw has been removed and that the bumper (Item
#19 on drawing) is in place in the shaft.
Install this sub assembly into the pump and secure by placing the outer chamber
housing and capscrews on the end with the diaphragm. This will hold the assembly
in place while the opposite side is installed. Make sure the last diaphragm assembly
is torqued to 30 ft. lbs. (40.67 Newton meters) before placing the outer diaphragm
over the capscrews. If the holes in the diaphragm flange do not line up with the holes
in the chamber flange, turn the diaphragm assembly in the direction of tightening
to align the holes so that the capscrews can be inserted. This final torquing of the
last diaphragm assembly will lock the two diaphragm assemblies together. Place
remaining outer chamber on the open end and tighten down the securing fasteners
gradually and evenly on both sides.
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 in-
ner chamber by removing the outer chamber assembly. Replace the bushings if pins
have bent.
TROUBLESHOOTING
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. Check valve not seating properly.
D. Leakage at joint of suction manifold or elbow flange.
E. Suction line or strainer plugged.
F. Diaphragm ruptured.
