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T31 SERIES
5.
PUMP ENDS
A.
Preliminary
B.
Disassembly
C.
Inspection of Components
D.
Reassembly
E.
Testing and Final Adjustments
5A Preliminary
Before attempting any service on the
pump or motor, disconnect the electrical
power to the pump motor. If the pump
and motor are to be removed as a
unit, note the wiring configuration. Use
colored or numbered tape to mark the
wire connections of the motor and power
source, for reconnection. If the pump is
being used to pump hot liquid, let the
pump and liquid cool before starting
disassembly.
1. Disconnect the inlet and outlet piping
before unbolting the pump and
motor. If the pipes are corroded, use
penetrating oil on the threads to aid
in removal.
2. Unbolt the motor from the base and
remove the unit. All work on the unit
should be performed on an elevated
workbench whenever possible.
5B Disassembly
The following tools and equipment are
needed for disassembly of T31 Series
Pumps:
1. Soft plastic or wooden mallet.
2. Small ball peen hammer.
3. 10mm wrench or socket
4. Snap ring pliers.
5. Penetrating oil.
6. 11/16" wood dowel (Approx. 6" long.)
7. Thin blade screwdriver.
8. Cealube G or similar glycol base
lubricant. (DO NOT use petroleum
products.)
To disassemble the pump:
Refer to Figure 5-2 for reference to
the numbered parts in the procedures
below.
1. Remove all liquid from the pump. Air
blown through the pump will remove
the water quickly.
2. Remove the four (4) M6-1 X 80mm
bolts (#19) from the cover (#2).
3. Remove the cover. In some cases
light tapping with a plastic or wooden
mallet on the outside diameter of the
cover may be required to loosen it
from the motor bracket. Care should
be taken if a screwdriver is needed
to pry between the cover and motor
bracket. Damage to the “O” ring (#7)
and/or impeller (#11) can result.
4. Remove the impeller. This is easily
done by setting the motor on end.
The impeller is a slip fit and under
normal conditions, can be removed
by hand or by gently tapping on the
end of the shaft with a mallet. Striking
the shaft too hard could damage the
seat, rotating element, or the motor.
After removing the impeller, the im-
peller key (#23) needs to be removed
from the shaft keyway.
5. Remove the snap ring (#4) from the
shaft; note the spring that is held in
place by the snap ring. Remove the
spring from the shaft.
6. To remove the rotating element
(#12), gently slide the motor bracket
(#1) forward on the shaft to move
the rotating element high enough to
be removed by hand. Using tools on
the rotating element may damage
the rotating element or the seat.
Take precautions to keep the rotating
element clean if it is to be reused.
7. Next remove the motor bracket.
8. To remove the seat (#125). Refer to
Figure 5-1. Place the motor bracket
face down on a clean flat surface.
Look into the opening in the center of
the motor bracket, and you will see a
portion of the seat. Insert the 11/16"
dowel and, very gently, tap the seat
until it drops out. Care must be taken
with the seat. It is often a brittle
material and is prone to breakage.
It is
recommended that a new re-
placement seat be installed during
reassembly.
5C Inspection of Components
Thoroughly clean all parts. All compo-
nents should be examined for wear and
corrosion. Replace any parts that show
visible wear. If the pump was not pro-
ducing sufficient pressure or capacity,
the clearances between the rings and
impeller probably exceed the maximum
allowable clearance. At minimum the
impeller should be replaced in this case.
If the total side running clearance for
an impeller exceeds .007", it is unlikely
that pump performance will reach that of
a new pump except at lower discharge
pressures.
The “O” rings and other elastomeric
components should be replaced if they
have been deformed or cut.
If seal components must be reused,
carefully inspect for microscopic cracks
and nicks. Scratches that might be
ignored elsewhere can produce leakage
if they are on seal carbons and seat
wearing surfaces.
Cleanliness is imperative when working
with mechanical seals. Almost unnotice-
able particles between seal faces can
be, and often are, the cause of early
seal failures.
Check the impeller; it is designed to
float. It should move easily on the shaft.
As long as it can be moved on the shaft
by hand, it is loose enough. If the impel-
ler can be rocked or wobbled, it is too
loose and must be replaced.
Check the shaft for galling, pitting, and
corrosion. If the shaft is corroded where
the seal comes in contact with the shaft,
Service
Figure 5-1
system periodically in the same way
as 4B. As an additional system check,
measure the temperature as it leaves
the heat exchanger. This can be done
with an external contact thermometer
or by adding an appropriate fitting and
internal thermometer. Cooling water
should be kept below 200°F. External
cooling water sources should be
checked for temperature and pressure.
Line pressure at the seal chamber fitting
must exceed that in the seal chamber
by at least 5 psi. Refer to the specific
instruction sheets for further cooling
system information.
4C Lubrication
Sealed ball bearings are standard in all
MTH pumps. The maximum continuous
operating temperature for bearings
is 250°F. While it is not advisable to
routinely disassemble sealed bearings,
it is possible to removes the seals
during disassembly and determine
their condition. Use new bearings
for reassembly. While the pump is in
service, listen for unusual sounds or
changes in bearing noise. A screwdriver
held between the bearing housing and
your ear while the pump is rotated by
hand is sometimes helpful if there is too
much ambient noise when the system is
operating.
