MTH M50 SERIES - Page 20

Page 520
17. Slide an Interstage Bushing (#16)
onto the shaft. The bushing
should be oriented such that the
end with the screw is further from
the motor and the screw head fi ts
into the slot in the right channel
ring. Refer to Figure 4-17.
This completes one stage; a stage
consists of one Left Hand Channel
Ring (#10), a Right Hand Channel Ring
(#9), and an Impeller (#11) between
them. Refer to Figure 4-12.
18. Install another Left Hand Channel
Ring (#10).
a. Install an Impeller Key (#23)
in the shaft.
b. Place an “O”Ring (#7) on the
raised step in the channel
ring. Lubricate the “O”ring
and inside lip in previous
channel ring.
c. Slide the channel ring
into place with the water
channel facing up. This time,
however, orient the large inlet
opening on the side opposite
of the pump inlet. Refer to
Figure 4-18.
19. Install another Impeller (#11),
remembering to point the impeller
hub towards the motor.
20. Install another Right Hand
Channel Ring (#9).
a. Place an “O”Ring (#7) on the
raised step in the channel
ring and lubricate.
b. Slide the channel ring onto
the guide rods with the water
channel facing down towards
the impeller. The small
outlet opening should be on
the opposite side from the
pump inlet. Refer to Figure
4-19. Push on fi rmly until the
“O”ring fi ts inside the lip in the
previously installed channel
ring.
21. Slide an Interstage Bushing (#16)
onto the shaft. The bushing
should be oriented such that the
end with the screw is further from
the motor and the screw head fi ts
into the slot in the right channel
ring. Refer to Figure 4-17.
Continue installing stages depending
on how many stages are in the
pump by repeating steps 14 through
21. Remember to stagger the ring
sets to balance radial loads. The
odd numbered stages should have
openings on the same side as the
pump inlet, as described in the fi rst
stage installation (steps 14 through
17). The even numbered stages
should have their openings on the
opposite side from the pump inlet, as
indicated (in steps 15 through 21).
22. Install one (1) “O”Ring (#8) on
each of the four Guide Rods (#18)
23. Replace the Plain Bearing
(#87) in the Outlet Cover (#2),
if it has been removed. If not,
proceed to step 24. The bearing
is an interference fi t and the
Outlet Cover must be heated
to approximately 300°F before
pressing in. Allow the Outlet
Cover to cool before proceeding
with the next step.
24. Install the Outlet Cover
a. Place an “O”Ring (#7) on
the raised step in the outlet
cover. You will need to
stretch the “O”Ring slightly to
do so.
b. Coat the “O”Ring and lip in
the last right channel ring (#9)
with a small amount of glycol
based lubricant.
c. With the “O”Ring facing the
last channel ring, slide the
Outlet Cover (#2) over the
Guide Rods. The outlet port
should be oriented 180° from
the inlet port on close coupled
units. The outlet port should
be oriented on the same side
as the inlet port on horizontal
units. Push on fi rmly until
the “O”Ring fi ts inside the lip
of the channel ring. Refer to
Figure 4-20.
25. Insert the eight (8) Thru Bolts
(#19) through the holes in the
outlet cover and the inlet cover.
Thread one (1) Nut (#20) on
each of the eight Thru Bolts and
on the end of each Guide Rod
(#18). Using two 9/16” wrenches
or sockets, tighten the bolts/
nuts systematically, alternating
diagonally across the cover, until
they are about one full turn short
of being fully torqued.
26. After the bolts/nuts are “snugged
up”, make sure the impellers are
not binding by inserting the 3/8”
hex wrench through the drain
hole in the Outlet Cover and in
the socket in the end of the shaft
and turn. The shaft should rotate
with little or no resistance. If the
shaft will not turn, loosen the bolts
equally until the impellers move
freely.
For C30 (close coupled) models
proceed to step 27. For models
on a P30 Bearing Frame, continue
assembling bearing frame as outlined
in Section 4F Reassembly P30 Bearing
Frames.
27. Remove the bolt installed in the
adapter shaft in step 10 used to
draw the shaft tapers together.
28. Install the motor over the endbell/
pump assembly and tighten the
four (4) long hex screws that
connect the motor to the endbell.
You may fi nd it easier to lay the
unit on its side for this operation.
29. Insert the motor Draw Bolt (#120)
into the hole in the motor shaft
(on the fan end) and thread it into
the pump shaft. Install the nut on
end of the stud and tighten. You
will need to hold the pump shaft
with the 3/8” hex wrench while
tightening.
30. Install the Drain Plug (#22) in the
Outlet Cover and install the fan
shroud on the motor.
Proceed to Section 4I Testing and
Final Adjustment.
4I Testing and Final Adjustments
The pump is now ready for installation.
Final adjustments will be made with the
pump in operation.
1. Reconnect the electrical
connections referring to the
colored or numbered tape used to
mark the wires.
2. Connect all piping and fi ll
the pump with fl uid . Ensure the
pump is properly primed and