MTH PUMPS T31 Series Setup guide

Section T31
Dated February 2011
Part No. 64-3520-01-588
T31 SERIES
Repair Instructions
PUMP ENDS

Section T31
Dated February 2011
Part No. 64-3520-01-588
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 conguration. 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 cor-
roded, 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 when-
ever possible.
T31 SERIES
Repair Instructions
5B Disassembly
The following tools and equipment
are needed for disassembly of T31
Series Pumps.
1. Soft plastic or wooden mallet.
2. Small ball pein 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 petro-
leum products.)
To disassemble the pump:
Refer to Figure 5-2 for reference to
the numbered parts in the proce-
dures 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 re-
quired 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.

Section T31
Dated February 2011
Part No. 64-3520-01-588
Figure 5-1
4. Remove the impeller. This is
easily done by setting the motor
on end. The impeller is a slip
t 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 impel-
ler, the impeller 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 rotat-
ing element or the seat. Take
precautions to keep the rotat-
ing 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 at 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 mate-
rial and is prone to breakage. It
is recommended that a new
replacement seat be installed
during reassembly.
5C Inspection of Components
Thoroughly clean all parts. All com-
ponents should be examined for
wear and corrosion. Replace any
parts that show visible wear. If the
pump was not producing sufcient
pressure or capacity, the clear-
ances between the motor bracket,
cover 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.

Section T31
Dated February 2011
Part No. 64-3520-01-588
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 unnoticeable particles be-
tween seal faces can be, and often
are, the cause of early seal failures.
Check the impeller; it is designed
to oat. 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 impeller can
be rocked or wobbled, it is too loose
and must be replaced.
Check the shaft for galling, pit-
ting, and corrosion. If the shaft is
corroded where the seal comes in
contact with the shaft, the motor
or bearing pedestal shaft must be
replaced. Surface corrosion must
be removed so that seals can slide
freely during assembly. The shaft
diameter should be no smaller than
.002” below the nominal fractional
seal sizes. Remove any nicks or
burrs which may have occurred
during disassembly. Re-clean parts
as necessary.
5D Reassembly
All parts should be visually in-
spected and cleaned or replaced as
outlined in 5C above.
1. The seal seat (#125) must be in-
stalled in the motor bracket (#1)
before the bracket is installed on
the motor. To install the seat:
a. Place the motor bracket face
up on a at surface.
b. Apply a coating of compat-
ible lubricant to the elastomer
portion of the seat to aid with
installation.
c. Carefully press the seat,
smooth side up, into the seat
cavity of the motor bracket.
Thumb pressure is usually
sufcient to install the seat.
2. Installing the motor bracket.
This is best done with the motor
standing on end. Make sure that
both the “C”-face of the motor
and the feet of the motor bracket
are clean. Slide the motor
bracket over the shaft onto the
motor.
3. Installing the rotating element
(#12). Lubricate the I.D. of the
rotating element. Place the
rotating element on the shaft with
the carbon end towards the seat.
Place the spring over the shaft,
with the backing plate up, and
compress the spring to locate
the rotating element against
the seat. If this fails to seat the
rotating element gently push the
rotating element down with a thin
blade screwdriver being careful
not to damage the seat or the
rotating element.
4. Compress and hold the seal
spring slightly below the snap
ring groove and install the snap
ring (#4). Make sure the snap
ring is locked in the groove.

Section T31
Dated February 2011
Part No. 64-3520-01-588
T31 CLOSE COUPLED PUMP
T31 SERIES
Repair Instructions
Figure 5-2
22
125
1
12
4 11 23
8
7
2
19
NAME/DESCRIPTION PART NO. QTY.
Motor Bracket 1 1
Cover 2 1
"O" Ring/Casing 7 1
"O" Ring/Tru Bolt 8 2
Snap Ring 4 1
Impeller 11 1
Seal Rotating Element 12 1
Seal Stationary Seat 125 1
Thru Bolt 19 4
Pipe Plug 22 1
Key/Impeller Drive 23 1

Section T31
Dated February 2011
Part No. 64-3520-01-588
5. Install the impeller key (#23) into
the shaft keyway.
6. The impeller is a slip t and
should slide on rmly but easily
until it stops against the impeller
wearing surface. Force should
not be required or used to install
the impeller in the correct posi-
tion. The impeller hub should be
facing out away from the motor
bracket. Refer to Figure 5-2.
7. Next, rotate the impeller by hand;
the impeller should move freely.
8. Place the large “O” ring (#7) into
the outside “O” ring groove in the
motor bracket. Place the two (2)
smaller “O” rings (#8) into the
smaller “O” ring grooves.
9. Place the cover (#2) over the
motor bracket and install the four
(4) M6-1 X 80mm bolts (#19).
Tighten the bolts systematically,
alternating diagonally across the
cover. DO NOT exceed 7-11 ft.
lbs. of torque or damage to the
motor “C”-face may occur.
5E Testing and Final Adjustment
The pump is now ready for instal-
lation. Final adjustments will be
made with the pump in operation.
1. Connect all piping and ll the
pump with uid.
2. Reconnect the electrical connec-
tions, referring to the colored or
numbered tape used to mark the
wires.
3. Make sure all valves are opened,
and uid will ow through the sys-
tem.
4. Start the pump and make the
nal adjustments to the M6 bolts
holding the cover on. These
bolts must be torqued to about
7-11 ft. lbs. to obtain proper
performance.
5. Check for leaks on pump and
piping. Special attention should
be given to the seal area at
the rear opening in the motor
bracket.
6. Under pressure, the impeller will
nd its “hydraulic” balance.
7. Using an amprobe or similar
device, check for motor overload.
8. While the impeller is seating, it
is common to experience some
variance in readings. After
a run-in period the readings
should level off.
This completes the adjustment and
testing phase. The pump is ready
for service.

Section T31
Dated February 2011
Part No. 64-3520-01-588
Installation Notes
Serial #: Install Date:
Distributor Name:
Maintenance & Service Record
Date Procedure
New pump installation into system

Section T31
Dated February 2011
Part No. 64-3520-01-588