MTH M50 SERIES - Page 16

Page 516
Refer to Figure 4-11 for reference to
the numbered parts in the reassembly
below.
1. Install the guide rods. Thread the
four (4) Guide Rods (#18) into the
motor or bearing frame face. It
is not necessary to turn them in
completely or tighten. About half
of the thread length should be
fi ne.
2. The Seat Stationary Seat (#125)
must be installed in the Inlet Cover
(#1 or #1IN) before the cover is
installed on the motor. To install
the seal seat:
a. Place the inlet cover face up
on a fl at surface.
b. Carefully press the seat,
smooth side up, into the
seat cavity of the inlet cover.
To make the installation
of the seat easier, apply a
thin coating of glycol base
lubricant to the elastomer
portion of the seat prior to
installation. Care must be
taken not to damage the seat
face. Thumb pressure is
usually suffi cient to install the
seat.
3. Install the Inlet Cover (#1 or 1IN).
a. Make sure the Drive Collar
(#14) is positioned on the
motor shaft.
b. While holding the inlet cover
with the inlet port 180° from
the motor conduit box (or
vertically on horizontal units),
slide the cover over the guide
rods on the face.
c. Slide the inlet cover back until
the feet are resting against
the face. Light tapping may
be necessary to seat the inlet
cover in the proper position.
d. Install one (1) “O” Ring (#8)
on each of the four guide
rods. This will help hold the
bracket in place during the
remainder of the assembly
operation.
4. On inducer pumps (L50 Series)
install one Snap Ring (#14A) in
the groove nearest the drive end
of the Shaft (#17), and slide the
Seal Driver (#88) on the shaft.
5. Install the Shaft (#17) and Seal
Rotating Element (#12) as a unit.
a. Lubricate the small end of
the shaft and the rotating
element.
b. Holding the element
assembly between the thumb
and index fi nger of both
hands, slide the assembly
over the shaft until the spring
holder rests against the
shoulder. Refer to Figure
4-13.
c. The element must slide freely
up and down the shaft. It is
necessary to maintain some
downward pressure on the
element because the spring
tension could dislodge the
seal portion of the element.
d. Install a Drive Key (#23A)
in the motor shaft before
installing the shaft and seal
assembly.
e. Align the keyway and slide
the pump shaft over the
motor shaft. Push the shaft in
until it comes in contact with
the drive collar.
f. Position the drive collar over
the shaft end and push the
shaft on until it stops.
g. While maintaining inward
pressure on the shaft with
one hand, line up the Collar
Setscrews (#15) with the key
in the motor shaft, placing
one setscrew on each side of
the keyway.
h. Using the hex wrench, tighten
the set screws snugly.
i. Pressure can now be
released, and the sleeve
should remain in position.
Make certain the spring
holder is below the
top surface of the seal
cavity for proper impeller
operation.
6. It is recommended that the
assembly be placed vertically
on the motor or pedestal end for
further assembly. Blocks can be
used to steady the unit.
For standard (M50 Series) pumps, skip
to step 9.
7. For inducer (L50 series), install the
Inducer Impeller (#11IN). Refer
to the L50 Inducer Stage Inset in
Figure 4-11.
a. Install an Impeller Key (#23)
in the shaft by the drive collar.
b. Slide the inducer impeller on
the shaft with the eye facing
the drive end.
c. Install the other Snap Ring
(#14A) on the shaft at the hub
of the inducer impeller.
8. Install the Diffuser Ring (#9IN).
a. Place an “O”Ring (#7) on
the raised step in the diffuser
ring. You will need to stretch
the “O”ring slightly to do so.
b. Coat the “O”ring and the lip
inside the inlet cover with a
small amount of glycol base
lubricant.
c. With the “O”ring facing the
inlet cover, slide the diffuser
ring onto the guide rods so
that it fi ts over the inducer
impeller. Push on fi rmly
until
the “O” ring fi ts inside the lip
in the inlet cover. Refer to
Figure 4-14.
Figure 4-14
9. Installation of the First Stage
a. Place the small “O”Ring
(#7A) in to the groove in the
hub of the inlet cover (#1
- 1IN) or Diffuser Ring (#9IN)
b. Install an Impeller Key (#23)
in the shaft.
c. Place an “O” ring (#7) on the
raised step in the channel