MTH PUMPS C41 Series User manual

C41 • C51 • C61 SERIES
Pump Manual
HORIZONTAL CLOSE COUPLED
Section C Page 501
Dated March 2017
97-5045-01-588

C41 • C51 • C61 SERIES
General Instructions
CENTRIFUGAL PUMPS
A. Inspection of Equipment
B. Storage
C. Placing Stored Pumps Into
Service
D. Recommended Spare
Parts
When properly installed and given
reasonable care and maintenance,
centrifugal pumps should operate
satisfactorily for many years. The
C Series pumps use tight running
clearances to build pressure.
Abrasive particles in high enough
concentrations, can eventually open
up the close clearances between
the impeller and the casing, thus
reducing pressure output. To avoid
this, careful selection and use of a
low resistance suction strainer should
be considered. For critical services
it is recommended that you keep an
identical pump for stand-by use.
1A Inspection of Equipment
Immediately upon receipt of the
shipment, inspect the equipment for
damage or missing components.
Check the shipping manifest and
report any damage or shortage to
the Transportation Company’s local
agent. Inspect the crate and any
wrapping material before discarding.
Parts or accessories are sometimes
wrapped individually or fastened to
the skid.
Put the instructions that came with
the shipment in a safe place where
they will be available to those who
will be using them for installation and
service.
1B Storage
If the pump is to be stored before
use, it should be inspected as
described in 1A, recrated and
stored in a dry location. Standard
shipping containers are not suitable
for outdoor storage. In some areas,
it may be necessary to cover the
pump’s exterior surface with oil or
other rust inhibiting coating. All units
are tested at the factory with a water/
corrosion inhibitor solution, some of
which will remain inside the pump
upon receipt. If units are ushed out
prior to storage, this inhibitor will be
removed and proper care must be
taken to prevent product deterioration
from improper storage.
For storage beyond 30 days, a
corrosion inhibiting protective uid
should be added to the internal pump
cavities. Fluids used in the pump
should be selected for compatibility
with pump materials. This is very
important when optional seal and
gasket materials have been used.
Protective caps on the inlet and
outlets should also be used. Caps
alone are not sufcient protection.
1C Application Considerations
1C1 Electrical Wiring
All electrical equipment and wiring
should conform to Local and
National Electrical Codes. Use the
motor manufacturer’s instructions
for connecting the motor. Note the
correct rotation and wiring diagrams
on the assembly. Make sure the
motor rotation and speed matches
that required for the pump. When
making electrical connections to
motors provided with threaded
stud electrical terminals, the
recommended torque should be
13-16 inch-lbs. Applying torque in
excess of this range may cause
damage.
1C2 Construction Materials
While it is reasonable to assume
that good judgement has been used
in selecting all the materials in the
pump for compatibility with process
uids, actual conditions sometimes
vary from original expectations. Also,
typical material selection charts do
not consider all the temperature,
pressure, and uid variables. The
customer’s engineer should be
consulted for nal judgment on the
best materials for critical process
applications.
1C3 Valves
If a shutoff valve is necessary in the
suction line, use a gate, ball, buttery,
or other full port valve. Globe or
other ow restricting valves, can in
some cases, reduce pump ow or
increase chances of cavitation.
A swing check valve in the suction
line is recommended even when
the pump inlet is only slightly higher
than the uid source to aid in
priming. It should be the same size
as the pump inlet or sized based on
reasonable uid friction losses.
A foot valve is recommended when
lifting uid from a sump. This will
save wear and tear on any pump,
even those equipped with self
priming equipment.
A low resistance Suction Strainer is
recommended immediately ahead of
the pump on any newly constructed
system. This is advisable due to the
probability that foreign material large
enough to damage pump clearances
may remain, even though the piping
has been ushed.
Valves in the outlet piping of a
centrifugal pump should be closed,
or nearly closed, when the pump is
started. This will reduce the start-up
load on the pump and motor. Never
start the pump with the discharge
valve fully open, unless system
friction losses are substantial enough
to prevent the pump from operating
at “run out,” otherwise cavitation or
motor overload may occur.
Inlet valving should be fully open
when starting any pumping system.
Without some uid in the pump at
startup, the unit can gall and lock up
the impeller. Always ll the pump
and vent it of air for best pump life.
Violent pump failure will result from
continued operation with the inlet
valve closed.
1C4 NPSH (Net Positive Suction
Head)
The NPSH required varies with
every size and capacity of pump.
The NPSH required by your unit can
be obtained from the performance
curves or from your MTH
representative.
If the NPSH available is not equal
to or greater than that required by
the pump, it must be increased or a
different pump selected. The usual
method for increasing NPSH is to
raise the static head on the pump
1.
Section C Page 502
Dated March 2017

inlet, (HS). By denition, NPSH
means: “Net Positive Suction
Head” above the vapor pressure
of the pumped liquid, available
at the centerline of the pump. It
should always be given in feet
of pumped liquid. The NPSH is
actually a measurement of the
amount of energy available in
the pumped liquid to produce
the required absolute entrance
velocity in the pump. If a pump
requires more energy (or NPSH)
than is available at a given
capacity, the pressure at the
inlet will fall below the vapor
pressure of the pumped liquid
and uid vaporization and loss of
performance will result.
P
s= Pressure in the suction
vessel in PSIA.
Pvp = Vapor pressure of the
pumped uid in PSIA.
Hs= Static height of the pumped
uid above (+) or below (-) the
centerline of the pump.
Hf= All friction losses from the
vessel to the pump.
NPSH = 2.31( )+Hs- Hf
P
s- P vp
S P. G R .
Section C Page 503
Dated March 2017
Pump Ends
A. Preliminary
B. Disassembly
C. Inspection of Components
D. Reassembly
E. Testing and Final Adjustments
2A 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.
Service
2.
1. Disconnect the inlet and
outlet piping before unbolting
the pump and motor.
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.
The disassembly and reassembly
procedures are broken into two
sections:
B — Disassembly
D — Reassembly
An exploded view of the unit,
Figure 1, is provided for referenc-
ing the numbers in the following
procedures, i.e. (#84), motor
bracket.
2B Disassembly
The following tools and equip-
ment are needed for disassembly.
1. Soft plastic or wooden mallet.
2. 5/8” wrench or socket.
3. 10 mm socket wrench.
4. 13 mm wrench or socket.
5. 5 mm Allen wrench.
For boiling liquids, Psand Pvp are
equal. This item then becomes
zero and can be omitted from the
equation.
1C5 Noise
Motors, bearings, and other
rotating components add to
noise, which sometimes create
objectionable harmonics.
Careful pump installation can
contribute to noise reduction.
Proper alignment of the pump
and driver is essential. Adequate
supports for the inlet and
discharge piping is equally
important. A degree of noise
reduction may be obtained when
the pumping unit is supported
free of building structures by the
use of vibration isolators, exible
piping and conduit connections.
To separate motor noise and
vibration from the uid and
piping structure, using a exible
elastomer-coupled (long coupled)
conguration is very desirable.
1C6 Freezing
When ambient temperatures
drop below the freezing point of
the uid, consideration should
be given to heating, insulating,
or draining the pump. If you
choose to drain the pump, rst
remove the drain plugs and drain
the suction and discharge lines.
Carefully blow out the pump
with compressed air to clear all
internal cavities of uid.
1D Recommended Spare Parts
FOR ROUTINE MAINTENANCE:
Only a complete set of “O” ring
gaskets and a mechanical seal
are recommended. Should ad-
ditional components show wear,
they are available from stock at
the factory (see the C Series
price brochure).
FOR SERVICING A PUMP THAT
DOES NOT PRODUCE RATED
CAPACITY OR HEAD :
“O” ring gaskets, impeller, me-
chanical seal, and pump casing.
FOR CRITICAL SERVICES:
A duplex installation, with two
identical pumping units in parallel,
is the safest, and many times the
most cost effective choice where
downtime cannot be tolerated.
C41 • C51 • C61 SERIES

84
108
7
11
12
125
5
7A
22
41 19
4
33A
8
20 33
23
C3A Motors
Figure 1
Section C Page 504
Dated March 2017
6. Penetrating oil.
7. 3/4” wood dowel (Approx. 6”
long).
8. Small O.D. Snap Ring Pliers.
9. Cealube G or similar glycol
base lubricant. (DO NOT use
petroleum products.)
To disassemble the pump:
1. Remove all liquid from the
pump.
2. Remove the casing (#108) by
removing the jam nuts (#20)
from the casing studs (#5).
Slide the casing off and rest it
on the studs.
3. Remove the impeller (#11) by
removing the 10mm Bolt (#19)
and washer (#41), then sliding
forward.(may require a gear
puller)
4. Remove the snap ring (#4)
from the shaft using snap ring
pliers.
5. Remove the impeller key (#23)
from the shaft.
6. Remove the rotating element
from the shaft.
The element normally adheres
tightly to the shaft and some
force may be necessary to re-
move it. This is common and, if
care is taken, the element can
be reassembled and reused. It
is recommended that a new
rotating element be used
for reassembly. DO
NOT attempt to remove the
seal using a screwdriver or
other sharp object. Extensive
damage to the shaft or element
could occur.
7. Remove the motor bracket.
Loosen and remove the four
socket head screws (#33A)
with a 5 mm Allen wrench.
Note: The rotating element
must be removed before the
motor bracket can be removed.
It is not necessary to remove
the adjusting screws # 33.
8. Remove the seat portion of the
seal from the motor bracket.
a. Place the motor bracket face
down on a at surface.
b. Look into the opening in the
center of the motor bracket,
you will see a portion of the
seat.
c. Insert the 3/4” dowel and,
very gently, tap the seat until
it drops out.
d. Care must be taken with
the seats. They are often
a brittle material and are
prone to breakage. It is
recommended that a new
replacement seat be in-
stalled during reassembly.
2C Inspection of Components
Thoroughly clean all parts. All
components should be examined
for wear and corrosion. Replace
any parts that show visible wear.
The “O” rings and other elas-
tomeric 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.

Section C Page 505
Dated March 2017
C41 • C51 • C61 SERIES
Service C SERIES PUMPS
Cleanliness is imperative when
working with mechanical seals.
Microscopic grit and particles
between seal faces can be, and
often are, the cause of early seal
failures.
If the impeller can be rocked or
wobbled on the shaft, it is too
loose and must be replaced.
Check the shaft for galling, pitting,
and corrosion. If the shaft is
corroded where the seal elasto-
mer comes in contact with it, the
motor 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.
2D Reassembly
All parts should be visually in-
spected and cleaned or replaced
as outlined in 2C above.
1. The seal seat (#125) must be
installed in the motor bracket
before the bracket is installed
on the motor.
To install the seat:
a. Place the motor bracket face
up on a at surface.
b. Carefully press the seat,
smooth side up, into the
seat cavity of the motor
bracket. To make the in-
stallation of the seat easier,
apply a very thin coating of
compatible seal lubricant
to the elastomer portion of
the seat prior to installation.
Care must be taken not
to damage the seat face.
Thumb pressure is usual-
ly sufcient to install the
seat. Make sure the seat is
installed rmly and squarely
and that it is then carefully
cleaned.
2. Install the motor bracket (#84).
a. This is best done with the
motor standing on end.
b. From the motor side: If
removed during disas-
sembly, thread the four (4)
adjusting screws (#33) into
the mounting anges of the
motor bracket until they are
ush with the front faces of
the anges.
c. Slide the four (4) small
“O”-rings (#8) fully onto the
socket head screws (#33A).
d. Place the motor bracket
(#84) on the motor. Slide
the bracket back until the
feet are resting against the
motor face. The orientation
of the motor bracket is not
critical unless a ush line is
used. In that case, align the
ush line to meet system
requirements.
e. Insert the four (4) socket
head screws (#33A) into
the motor bracket holes and
thread into the motor face.
Tighten securely using a 5
mm Allen wrench. Do not
exceed 7 ft-lbs of torque or
damage to the motor “C”-
face may occur.
3. Install rotating element (#12).
a. Tip the pump assembly over
into a horizontal position on
the work area.
b. Lightly lubricate the motor
shaft. Push the rotating
element, spring, and then
spring holder over the shaft.
Figure 2
NAME / DESCRIPTION KEY NO. QTY
Motor Bracket 84 1
Casing 108 1
“O” Ring - Casing** 7 1
Impeller 11 1
Seal - Rotating Element** 12 1
Seal - Stationary Seat** 125 1
Stud - Casing 5 4
Jam Nut 20 4
Adjusting Screw 33 4
Socket Head Screw 33A 4
“O” Ring - Screw** 8 4
Snap Ring** 4 1
Drive Key** 23 1
Impeller Screw 19 1
Washer 41 1
Drain Plug (SAE) 22 1
“O”Ring - Drain** 7A 2
**Included in SKC4100, SKC5100, SKC6100 Mechanical Seal / O Ring Kits

C41 • C51 • C61 SERIES
Service
Section C Page 505
Dated March 2017
c. Prepare the snap ring in the
snap ring pliers and then
compress and hold the seal
spring slightly below the
snap ring groove. Install the
snap ring (#4). Make sure
the snap ring is locked in the
groove.
4. Install the impeller (#11).
a. Place the key (#23) in the
shaft sleeve.
b. The impeller should slide
on rmly, but easily, until it
stops. Force should not be
required to install the impel-
ler in the correct position.
c. The impeller hub should be
facing toward the motor.
d. Apply Locktite 277 to the
threads on the screw (#19),
then fasten the impeller
using the washer (#41)
and screw (#19). Tighten
the screw securely (do not
exceed 7 ft-lbs of torque),
while holding the impeller
stationary. The impeller
should not have any play
or wobble.
5. Install the casing (#108).
a. Hand tighten four (4) studs
(#5) into the casing until they
are seated.
b. Lubricate and install the
casing “O”-ring (#7) onto the
rst step in the motor brack-
et.
c. Place the casing over the
motor bracket being careful
not to pinch the “O”-ring.
The casing discharge should
be oriented to meet system
requirements.
d. Loosely thread four (4) jam
nuts (#20) onto the casing
studs.
6. Adjusting Impeller/Casing
Clearance
a. Seat the casing down
against the impeller with
light hand pressure.
b. Turn the adjusting screws
until they just touch the back
face of the casing. The cas-
ing should not move during
this adjustment. This will de-
termine the zero clearance
position. Set the minimum
free running clearance as
follows:
i. Viewing from the back
of the motor bracket,
(rear of motor) turn each
adjusting screw clockwise
exactly 30° (1/12 of a full
revolution).
ii. Securely tighten the four
(4) jam nuts against the
adjusting nuts using a
9/16” wrench and a 5/8”
wrench, being careful to
prevent the adjusting nuts
from turning.
c. Turn the impeller clockwise
and listen for any scraping
noises or interference. This
may be done by turning the
impeller screw with a 10 mm
socket through the inlet port
(Be careful not to loosen the
screw), and listening through
the discharge. If any contact
is detected between the
impeller and casing, perform
the following steps:
i. Loosen the jam nuts,
being careful not to turn
the adjusting nuts.
ii. Repeat steps 6.b.i and
6.b.ii.
iii. Repeat step 6.c.
2E TESTING AND FINAL
ADJUSTMENT
The pump is now ready for instal-
lation.
1. Reconnect the electrical con-
nections referring to the colored
or numbered tape used to mark
the wires during disassembly.
2. Connect all piping and ll the
pump with uid.
3. Make sure all suction valves
are opened and uid will ow
through the system. Discharge
valve should be partially opened.
4. Start the pump and check for
leaks on the pump and piping.
Special attention should be given
to the seal area at the rear open-
ing in the motor bracket.
5.Using an amprobe or similar
device, check for motor overload.
If motor is overloading it is pos-
sible that the impeller clearance
was not properly set as outlined
in Step 6 outlined in “D” Reas-
sembly.

Section C Page 506
Dated March 2017
C41 • C51 • C61 SERIES
A. Parts
B. Repair Service
C. Warranty Service
6A Parts
Repair parts may be obtained
through your local Authorized
MTH Pumps Distributor who may
be found in the yellow pages or
by contacting:
MTH Pumps
401 W. Main St.
Plano, IL 60545
Phone: [phone]
Fax: [phone]
Email: [email protected]
Web: WWW.MTHPumps.com
3.
6B Repair Services
Repair service for an MTH pump
should be obtained from the
company through which it was
purchased.
In the event this is not possible,
the name and phone number of
a nearby MTH representative
or distributor may be obtained
by contacting MTH Pumps. In
the event that it is necessary to
return the pump to the factory for
repairs, remove all accessories
attached to the pump. We cannot
accept responsibility for their safe
removal, storage, and return.
6C Warranty Service
All requests for warranty claims
should be made through the
company from which the pump
was purchased or supplied.
Complete details on what is
wrong with the pump must be
provided along with information
on the system in which it is
installed. Refer to the MTH
Pumps Limited Warranty
statement. Return authorization
must be obtained prior to
returning any equipment.
Parts and Repair Services

Section C Page 508
Dated March 2017
97-5045-01-588
4.Limited Warranty
C41 • C51 • C61 SERIES
MTH makes good faith recommendations of Products, based on its experience and the application information provided by the Purchaser. However, the re-
sponsibility for testing and approving a Product to be used for a particular purpose lies with the Purchaser.
The obligations of MTH Tool Company, Inc. (hereinafter referred to as “MTH”), with respect to a “Product” (dened below) are limited as set forth herein.
ALL IMPLIED WARRANTIES, including the “implied warranty of merchantability” and the “implied warranty of fitness for a particular purpose” are
HEREBY DISCLAIMED.
There are no warranties which extend beyond the description on the face hereof.
MTH warrants that, during the “Warranty Period” (dened below), the “Product” (dened below) will not fail to meet the “Operational Specications” (dened
below), within applicable industry tolerances established by the Hydraulic Institute, due to defects in its materials and workmanship. MTH does not warrant that
any Product will meet the “Operational Specications” in conditions other than the Standard Operating Conditions, unless agreed to by MTH in a signed writing.
For all purposes of this Limited Warranty:
(a) The term “Warranty Period” shall mean the twelve (12) month period from the date of shipment from MTH to the Purchaser (the “Warranty
Period”).
(b) The term “Product” shall mean: any item or assembly of items sold by MTH that are either manufactured or selected by MTH to meet the
“Operational Specications”. The term “Product” does not include any item, assembly of items, or portion of such assembly that is selected or
specied by any entity other than MTH, or that MTH has identied as ineligible for warranty coverage.
(c) The term "Purchaser" shall mean the original person(s) or entity that issued the purchase order to MTH, for the Product.
(d) The term “Operational Specications” shall mean the specied dimensions, material composition, and performance parameters of a Product,
as published by MTH, or as otherwise agreed in a signed writing between MTH and Purchaser. “Standard Operating Conditions”, for pumps,
shall mean: operating with clean water, at standard temperature and pressure. “Operational Specications” shall not include visual appearance or
any other parameters not expressly agreed to in writing.
If, within the Warranty Period, a Purchaser believes that a Product has failed to meet its Operational Specications, the Purchaser must request a Return Goods
Authorization (“RGA”) in the manner specied at http://www.mthpumps.com, and supply any additional information MTH might reasonably request. If the Product
was purchased through a distributor or any entity other than MTH, the RGA request must be made through that entity. Any Product returned without an RGA will
be refused at the dock. Products authorized for return must be properly packaged to prevent further damage, clearly marked with the Return Goods Authorization
“RGA” number provided by MTH, and shipped freight prepaid and allowed, F.O.B. the MTH factory at Plano, Illinois, USA.
MTH may, in its sole discretion, deny any warranty claim if shipping damage, any attempted disassembly, or any other action outside of MTH’s control impairs
MTH’s determination of the existence of, or cause of a claimed failure.
Notwithstanding anything to the contrary in this Limited Warranty, MTH shall have no obligation to repair or replace any Product it determines to have any
defects arising from or attributable to: (1) abrasion, corrosion, or erosion arising after shipment from MTH; (2) improper handling, packaging, installation, storage,
or maintenance, after it is shipped by MTH; (3) repairs or alterations outside of MTH’s factory, in any manner, without MTH’s written authorization; (4) misuse,
negligence, or accident after shipment from MTH; (5) use in a manner inconsistent with MTH’s published instructions and Operational Specications, or other
written specications agreed to by both Purchaser and MTH; or (6) incorrect power supply or power quality. MTH’s determination with respect to the applicability
of this Limited Warranty to any particular defect or Product shall be nal and conclusive.
If, after examination by an authorized representative of MTH, MTH determines that the Product failed to meet the “Operational Specications”, within applicable
industry tolerances established by the Hydraulic Institute, due to defects in its materials and workmanship, during the Warranty Period, then MTH will, at its option,
ship a repaired or replaced Product to the Purchaser, F.O.B. MTH’s factory in Plano, Illinois, U.S.A., freight prepaid and allowed. MTH will use a freight provider
of its choosing, via a method no faster than that used for shipping the Product to MTH. MTH may, at its sole discretion, issue a credit memo to Purchaser for
some or all Purchaser’s shipping costs to return a defective Product to MTH.
MTH accepts no responsibility for costs associated with removal and reinstallation of Products.
Under no circumstances shall MTH be liable for incidental or consequential damages.
MTH neither assumes responsibility for, nor authorizes any person to assume for it, any other obligation in connection with the sale of any Product or any
enlargement of this Limited Warranty.
Some States do not allow the exclusion or limitation of incidental or consequential damages. So, the above limitations or exclusions might not apply
to you. This warranty gives you specific legal rights, and you might, also, have other rights, which vary from State to State.
By using this Product, you agree that this Limited Warranty is governed by the laws of the State of Illinois; that this Limited Warranty shall be inter-
preted and enforced only in accordance with the laws of the State of Illinois (excluding its conflicts of law provisions); and that you submit yourself
to the jurisdiction of the 23rd Judicial Circuit, Kendall County, Illinois, which shall have exclusive jurisdiction over any controversy or dispute arising
under or with regard to this Limited Warranty.
!WARNING:
CANCER AND REPRODUCTIVE HARM -
WWW.P65WARNINGS.CA.GOV
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