ITT Goulds Pumps 3755 User manual

Installation, Operation, and
Maintenance Manual
Model 3755

Table of Contents
1 Introduction and Safety ....................................................................................................................................3
1.1 Important Safety Notice.............................................................................................................................3
1.2 Safety warnings.........................................................................................................................................3
1.3 Safety ........................................................................................................................................................4
1.4 General precautions .................................................................................................................................. 5
1.5 ATEX Considerations and Intended Use.................................................................................................. 8
1.6 Parts .......................................................................................................................................................... 9
2 Installation........................................................................................................................................................10
2.1 Location...................................................................................................................................................10
2.2 Prepare the foundation............................................................................................................................10
2.3 Alignment - initial ..................................................................................................................................... 11
2.4 Piping - general .......................................................................................................................................14
2.5 Install suction piping ................................................................................................................................ 14
2.6 Piping - discharge.................................................................................................................................... 15
2.7 Connection of piping................................................................................................................................ 16
2.8 Check rotation .........................................................................................................................................16
2.9 Connection of coupling............................................................................................................................16
3 Preparation for Operation...............................................................................................................................17
3.1 Pump bearings ........................................................................................................................................17
3.2 Driver bearings ........................................................................................................................................ 18
3.3 Stuffing box ............................................................................................................................................. 18
3.4 Connection of sealing liquid or greased lubricator (packed box)............................................................. 19
3.5 Connection to quenching gland...............................................................................................................19
3.6 Connection of cooling water piping ......................................................................................................... 19
3.7 Connection of drain piping....................................................................................................................... 20
4 Starting Pump..................................................................................................................................................21
4.1 Priming ....................................................................................................................................................21
4.2 Adjustment of stuffing box gland .............................................................................................................21
4.3 Alignment - final....................................................................................................................................... 21
4.4 Doweling.................................................................................................................................................. 21
5 Operation..........................................................................................................................................................22
5.1 Stuffing box ............................................................................................................................................. 22
5.2 Operating at reduced capacities.............................................................................................................. 22
5.3 Operating at reduced head...................................................................................................................... 23
5.4 Operating with surge conditions in line.................................................................................................... 23
5.5 Operating under freezing conditions ....................................................................................................... 23
6 Trouble Check List .......................................................................................................................................... 24
6.1 No liquid delivered...................................................................................................................................24
6.2 Not enough liquid delivered.....................................................................................................................24
6.3 Not enough pressure...............................................................................................................................24
6.4 Pump works a while and then quits.........................................................................................................25
6.5 Pump takes too much power...................................................................................................................25
6.6 Pump leaks excessively at stuffing box...................................................................................................25
6.7 Pump is noisy or vibrates ........................................................................................................................26
Table of Contents
Model 3755 Installation, Operation, and Maintenance Manual 1

7 Care and Maintenance ....................................................................................................................................27
7.1 Lubrication...............................................................................................................................................27
7.2 Repacking stuffing box ............................................................................................................................ 27
7.3 Replacing shaft sleeve ............................................................................................................................27
7.4 Sectional views, parts list and interchangeability tables ......................................................................... 29
7.5 Wearing rings ..........................................................................................................................................31
7.6 Replacing impeller...................................................................................................................................32
7.7 Replacing shaft or bearings..................................................................................................................... 33
7.8 Replacing casing ..................................................................................................................................... 36
7.9 Spare parts..............................................................................................................................................36
7.10 Instructions for ordering spare parts...................................................................................................... 37
Table of Contents
2 Model 3755 Installation, Operation, and Maintenance Manual

1 Introduction and Safety
1.1 Important Safety Notice
To: Our Valued Customers:
User safety is a major focus in the design of our products. Following the precautions outlined in this man-
ual will minimize your risk of injury.
ITT Goulds pumps will provide safe, trouble-free service when properly installed, maintained, and operat-
ed.
Safe installation, operation, and maintenance of ITT Goulds Pumps equipment are an essential end user
responsibility. This Pump Safety Manual identifies specific safety risks that must be considered at all
times during product life. Understanding and adhering to these safety warnings is mandatory to ensure
personnel, property, and/or the environment will not be harmed. Adherence to these warnings alone,
however, is not sufficient — it is anticipated that the end user will also comply with industry and corporate
safety standards. Identifying and eliminating unsafe installation, operating and maintenance practices is
the responsibility of all individuals involved in the installation, operation, and maintenance of industrial
equipment.
Please take the time to review and understand the safe installation, operation, and maintenance guide-
lines outlined in this Pump Safety Manual and the Instruction, Operation, and Maintenance (IOM) man-
ual. Current manuals are available at https://www.gouldspumps.com/en-US/Tools-and-Resources/Litera-
ture/ or by contacting your nearest Goulds Pumps sales representative.
These manuals must be read and understood before installation and start-up.
For additional information, contact your nearest Goulds Pumps sales representative or visit our Web site
at https://www.gouldspumps.com
1.2 Safety warnings
Specific to pumping equipment, significant risks bear reinforcement above and beyond normal safety
precautions.
WARNING:
A pump is a pressure vessel with rotating parts that can be hazardous. Any pressure vessel
can explode, rupture, or discharge its contents if sufficiently over pressurized causing death,
personal injury, property damage, and/or damage to the environment. All necessary measures
must be taken to ensure over pressurization does not occur.
WARNING:
Operation of any pumping system with a blocked suction and discharge must be avoided in all
cases. Operation, even for a brief period under these conditions, can cause superheating of
enclosed pumpage and result in a violent explosion. All necessary measures must be taken by
the end user to ensure this condition is avoided.
WARNING:
The pump may handle hazardous and/or toxic fluids. Care must be taken to identify the con-
tents of the pump and eliminate the possibility of exposure, particularly if hazardous and/or tox-
ic. Potential hazards include, but are not limited to, high temperature, flammable, acidic, caus-
tic, explosive, and other risks.
1 Introduction and Safety
Model 3755 Installation, Operation, and Maintenance Manual 3

WARNING:
Pumping equipment Instruction, Operation, and Maintenance manuals clearly identify accepted
methods for disassembling pumping units. These methods must be adhered to. Specifically,
applying heat to impellers and/or impeller retaining devices to aid in their removal is strictly for-
bidden. Trapped liquid can rapidly expand and result in a violent explosion and injury.
ITT Goulds Pumps will not accept responsibility for physical injury, damage, or delays caused by a failure
to observe the instructions for installation, operation, and maintenance contained in this Pump Safety
Manual or the current IOM available at http://www.gouldspumps.com/literature.
1.3 Safety
Definitions
Throughout this manual the words Warning, Caution, Electrical, and ATEX are used to indicate where
special operator attention is required.
Observe all Cautions and Warnings highlighted in the Pump Safety Manual and the IOM provided with
your equipment.
WARNING:
Indicates a hazardous situation which, if not avoided, could result in death or serious injury.
Example: Pump shall never be operated without coupling guard installed correctly.
CAUTION:
Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury.
Example: Throttling flow from the suction side may cause cavitation and pump damage.
Electrical Hazard:
WARNING:
Indicates the possibility of electrical risks if directions are not followed.
Example: Lock out driver power to prevent electric shock, accidental start-up, and physical in-
jury.
ATEX:
WARNING:
When installed in potentially explosive atmospheres, the instructions that follow the Ex symbol
must be followed. Personal injury and/or equipment damage may occur if these instructions are
not followed. If there is any question regarding these requirements or if the equipment is to be
modified, please contact an ITT Goulds Pumps representative before proceeding.
Example: Improper impeller adjustment could cause contact between the rotating and station-
ary parts, resulting in a spark and heat generation.
1.3 Safety
4 Model 3755 Installation, Operation, and Maintenance Manual

1.4 General precautions
WARNING:
A pump is a pressure vessel with rotating parts that can be hazardous. Hazardous fluids may
be contained by the pump including high temperature, flammable, acidic, caustic, explosive,
and other risks. Operators and maintenance personnel must realize this and follow safety
measures. Personal injuries will result if procedures outlined in this manual are not followed.
ITT Goulds Pumps will not accept responsibility for physical injury, damage or delays caused
by a failure to observe the instructions in this manual and the IOM provided with your equip-
ment.
Table 1: General Precautions
WARNING NEVER APPLY HEAT TO REMOVE IMPELLER. It may explode due to trap-
ped liquid.
WARNING NEVER use heat to disassemble pump due to risk of explosion from tapped
liquid.
WARNING NEVER operate pump without coupling guard correctly installed.
WARNING NEVER run pump below recommended minimum flow when dry, or without
prime.
WARNING ALWAYS lock out power to the driver before performing pump maintenance.
WARNING NEVER operate pump without safety devices installed.
WARNING NEVER operate pump with discharge valve closed.
WARNING NEVER operate pump with suction valve closed.
WARNING DO NOT change service application without approval of an authorized ITT
Goulds Pumps representative.
WARNING Safety Apparel:
•Insulated work gloves when handling hot bearings or using bearing
heater
• Heavy work gloves when handling parts with sharp edges, especially
impellers
• Safety glasses (with side shields) for eye protection
• Steel-toed shoes for foot protection when handling parts, heavy tools,
etc.
• Other personal protective equipment to protect against hazardous/toxic
fluids
WARNING Receiving:
Assembled pumping units and their components are heavy. Failure to properly
lift and support equipment can result in serious physical injury and/or
1.4 General precautions
Model 3755 Installation, Operation, and Maintenance Manual 5

equipment damage. Lift equipment only at specifically identified lifting points
or as instructed in the current IOM. Current manuals are available at
www.gouldspumps.com/literature_ioms.html or from your local ITT Goulds
Pumps sales representative. Note: Lifting devices (eyebolts, slings, spreaders,
etc.) must be rated, selected, and used for the entire load being lifted.
WARNING Alignment:
Shaft alignment procedures must be followed to prevent catastrophic failure of
drive components or unintended contact of rotating parts. Follow coupling
manufacturer's coupling installation and operation procedures.
WARNING Before beginning any alignment procedure, make sure driver power is locked
out. Failure to lock out driver power will result in serious physical injury.
CAUTION Piping:
Never draw piping into place by forcing at the flanged connections of the
pump. This may impose dangerous strains on the unit and cause misalign-
ment between pump and driver. Pipe strain will adversely effect the operation
of the pump resulting in physical injury and damage to the equipment.
WARNING Flanged Connections:
Use only fasteners of the proper size and material.
WARNING Replace all corroded fasteners.
WARNING Ensure all fasteners are properly tightened and there are no missing fasten-
ers.
WARNING Startup and Operation:
When installing in a potentially explosive environment, please ensure that the
motor is properly certified.
WARNING Operating pump in reverse rotation may result in contact of metal parts, heat
generation, and breach of containment.
WARNING Lock out driver power to prevent accidental start-up and physical injury.
WARNING The impeller clearance setting procedure must be followed. Improperly setting
the clearance or not following any of the proper procedures can result in
sparks, unexpected heat generation and equipment damage.
WARNING If using a cartridge mechanical seal, the centering clips must be installed and
set screws loosened prior to setting impeller clearance. Failure to do so could
result in sparks, heat generation, and mechanical seal damage.
WARNING The coupling used in an ATEX classified environment must be properly certi-
fied and must be constructed from a non-sparking material.
WARNING Never operate a pump without coupling guard properly installed. Personal in-
jury will occur if pump is run without coupling guard.
1.4 General precautions
6 Model 3755 Installation, Operation, and Maintenance Manual

WARNING Make sure to properly lubricate the bearings. Failure to do so may result in ex-
cess heat generation, sparks, and / or premature failure.
CAUTION The mechanical seal used in an ATEX classified environment must be proper-
ly certified. Prior to start up, ensure all points of potential leakage of process
fluid to the work environment are closed.
CAUTION Never operate the pump without liquid supplied to mechanical seal. Running a
mechanical seal dry, even for a few seconds, can cause seal damage and
must be avoided. Physical injury can occur if mechanical seal fails.
WARNING Never attempt to replace packing until the driver is properly locked out and the
coupling spacer is removed.
WARNING Dynamic seals are not allowed in an ATEX classified environment.
WARNING DO NOT operate pump below minimum rated flows or with suction and/or dis-
charge valve closed. These conditions may create an explosive hazard due to
vaporization of pumpage and can quickly lead to pump failure and physical in-
jury
WARNING Ensure pump is isolated from system and pressure is relieved before disas-
sembling pump, removing plugs, opening vent or drain valves, or disconnect-
ing piping.
WARNING Shutdown, Disassembly, and Reassembly:
Pump components can be heavy. Proper methods of lifting must be employed
to avoid physical injury and/or equipment damage. Steel toed shoes must be
worn at all times.
WARNING The pump may handle hazardous and/or toxic fluids. Observe proper decon-
tamination procedures. Proper personal protective equipment should be worn.
Precautions must be taken to prevent physical injury. Pumpage must be han-
dled and disposed of in conformance with applicable environmental regula-
tions.
WARNING Operator must be aware of pumpage and safety precautions to prevent physi-
cal injury.
WARNING Lock out driver power to prevent accidental startup and physical injury.
CAUTION Allow all system and pump components to cool before handling them to pre-
vent physical injury.
CAUTION If pump is a Model NM3171, NM3196, 3198, 3298, V3298, SP3298, 4150,
4550, or 3107, there may be a risk of static electric discharge from plastic
parts that are not properly grounded. If pumped fluid is non-conductive, pump
should be drained and flushed with a conductive fluid under conditions that
will not allow for a spark to be released to the atmosphere.
WARNING Never apply heat to remove an impeller. The use of heat may cause an explo-
sion due to trapped fluid, resulting in severe physical injury and property dam-
age.
CAUTION Wear heavy work gloves when handling impellers as sharp edges may cause
physical injury.
CAUTION Wear insulated gloves when using a bearing heater. Bearings will get hot and
can cause physical injury.
1.4 General precautions
Model 3755 Installation, Operation, and Maintenance Manual 7

WARNING Noise:
Sound pressure levels may exceed 80 dbA in operating process plants. Clear
visual warnings or other indicators should be available to those entering an
area with unsafe noise levels. Personnel should wear appropriate hearing pro-
tection when working on or around any equipment, including pumps. Consider
limiting personnel’s exposure time to noise or, where possible, enclosing
equipment to reduce noise. Local law may provide specific guidance regard-
ing exposure of personnel to noise and when noise exposure reduction is re-
quired.
WARNING Temperature:
Equipment and piping surfaces may exceed 130ºF (54ºC) in operating proc-
ess plants. Clear visual warnings or other indicators should alert personnel to
surfaces that may reach a potentially unsafe temperature. Do not touch hot
surfaces. Allow pumps operating at a high temperature to cool sufficiently be-
fore performing maintenance. If touching a hot surface cannot be avoided,
personnel should wear appropriate gloves, clothing, and other protective gear
as necessary. Local law may provide specific guidance regarding exposure of
personnel to unsafe temperatures.
1.5 ATEX Considerations and Intended Use
Special care must be taken in potentially explosive environments to ensure that the equipment is proper-
ly maintained. This includes but is not limited to:
Description of ATEX
The ATEX directives are a specification enforced in Europe for electrical and non-electrical equipment
installed in Europe. ATEX deals with the control of potentially explosive atmospheres and the standards
of equipment and protective systems used within these atmospheres. The relevance of the ATEX re-
quirements is not limited to Europe. You can apply these guidelines to equipment installed in any poten-
tially explosive atmosphere.
Guidelines for compliance
Compliance is fulfilled only when you operate the unit within its intended use. Do not change the condi-
tions of the service without the approval of an ITT representative. When you install or maintain explosion
proof products, always comply with the directive and applicable standards (for example, IEC/EN
60079-14).
1. Monitoring the and liquid end temperature.
2. Maintaining proper bearing lubrication.
3. Ensuring that the pump is operated in the intended hydraulic range.
The ATEX conformance is only applicable when the pump unit is operated within its intended use. Oper-
ating, installing or maintaining the pump unit in any way that is not covered in the Instruction, Operation,
and Maintenance manual (IOM) can cause serious personal injury or damage to the equipment. This in-
cludes any modification to the equipment or use of parts not provided by ITT Goulds Pumps. If there is
any question regarding the intended use of the equipment, please contact an ITT Goulds representative
before proceeding.
Current IOMs are available at https://www.gouldspumps.com/en-US/Tools-and-Resources/Literature/
IOMs/ or from your local ITT Goulds Pumps Sales representative.
1.5 ATEX Considerations and Intended Use
8 Model 3755 Installation, Operation, and Maintenance Manual

All pumping unit (pump, seal, coupling, motor and pump accessories) certified for use in an ATEX classi-
fied environment, are identified by an ATEX tag secured to the pump or the on which it is mounted. A
typical tag would look like this:
Figure 1: Typical ATEX pump nameplate
Table 2: Temperature class definitions
Code Maximum permissible
pumpage temperature in °C | °F
Minimum permissible pumpage temperature in °C | °F
T1 450 | 842 372 | 700
T2 300 | 572 277 | 530
T3 200 | 392 177 | 350
T4 135 | 275 113 | 235
T5 100 | 212 Option not available
T6 85 | 185 Option not available
The code classification marked on the equipment must be in accordance with the specified area where
the equipment will be installed. If it is not, do not operate the equipment and contact your ITT Goulds
Pumps sales representative before proceeding.
The code classification marked on the equipment must be in accordance with the specified area where
the equipment will be installed. If it is not, do not operate the equipment and contact your ITT Goulds
Pumps sales representative before proceeding.
1.6 Parts
The use of genuine Goulds parts will provide the safest and most
reliable operation of your pump. ITT Goulds Pumps ISO certifica-
tion and quality control procedures ensure the parts are manufac-
tured to the highest quality and safety levels.
Please contact your local Goulds representative for details on
genuine Goulds parts.
1.6 Parts
Model 3755 Installation, Operation, and Maintenance Manual 9

2 Installation
2.1 Location
Pumping unit should be placed as close as practical to the source of supply. Always allow sufficient head
room to remove the upper half casing of the pump and the rotating element. Floor space allotted to the
pumping unit should be sufficient for inspection and maintenance.
2.2 Prepare the foundation
1. The foundation should be substantial in order to absorb any vibration and to form a permanent rigid
support for the bedplate. A concrete foundation poured on a solid footing, using a one-three-five
mix, of a liberal thickness to support the pumping unit is satisfactory.
2. Foundation Bolts:
a) The location and size of the foundation bolts is shown on the outline assembly drawing sup-
plied for the pumping unit.
b) Each bolt should be installed with a pipe sleeve around it - to allow for adjustment. The inside
sleeve diameter should be 2½ to 3 times the diameter of the bolt. Place a washer between bolt
head and sleeve to hold bolt in position. Stuff waste around foundation bolts to prevent con-
crete from entering between the bolt and pipe sleeve. See Figure 2: Foundation on page 10.
c) The foundation bolts should be of sufficient length so that they project through the nut approxi-
mately ¼" after allowance has been made for grouting (¾" to 1½"), the thickness of the bed-
plate, and the thickness of the foundation bolt nut. See Figure 2: Foundation on page 10.
Figure 2: Foundation
3. Preparing Foundation for Mounting:
Prior to setting unit upon the foundation, clean the top surface of concrete.
4. Mounting unit on foundation
a) Put the pumping unit in place on the wedges. The wedges should be placed at four points, two
below the approximate center of the pump and two below the approximate center of the driver
(See Figure 2). Some installations may require additional wedges near the middle of the bed-
plate.
b) Disconnect coupling between pump and driver if other than insert-spider type.
c) By adjustment of the wedges, bring the unit to an approximate level and provide for the proper
distance above the foundation for grouting (¾" to 1½"). Plumb the suction and discharge flang-
es. By further adjustment of the wedges, bring the coupling halves into reasonable alignment.
Check by method described in Section 2.3 Alignment - initial on page 11, steps 4 through 6.
d) After the wedges have been adjusted, tighten foundation bolts evenly but only finger tight.
2 Installation
10 Model 3755 Installation, Operation, and Maintenance Manual

NOTICE:
Final tightening of foundation bolts is done after grout has set 48 hours.
Figure 3:
5. Grouting Unit on Foundation:
a) Build wood dam around foundation as shown in Figure 2: Foundation on page 10. Wet top sur-
face of concrete foundation thoroughly.
b) Pour grout in hole provided in the top of the bedplate. Use of a non-shrink grout is recommend-
ed. The grout should be thin enough to flow out under the bedplate. A mixture of one part Port-
land cement to three parts sharp sand may also be used. Cement grout should not be so thin
that the cement will separate from the sand.
c) The grout should be puddled continuously as it is poured to expel the air and completely fill the
space under the bedplate, to the level of the grout hole in the top of the bedplate.
d) With a trowel, strike along the top of the wood dam to give a neat, finished appearance at this
point.
e) Allow grout to harden at least 48 hours.
2.3 Alignment - initial
Alignment of the pump and driver through the flexible coupling is of extreme importance for trouble-free
mechanical operation.
If the driver was mounted at the factory, the unit was in alignment before it left our assembly department.
However, in transit and subsequent handling, this factory alignment was probably destroyed; and, it is
now necessary to reestablish the alignment. As directed in Foundation (Step 4, Mounting unit on founda-
tion), only approximate alignment was obtained by wedging under bedplate before grouting.
The following are suggested steps to establish the initial alignment of the pumping unit.
NOTICE:
This is an initial alignment. The final alignment is done after the unit has been run under actual
operating conditions. The final alignment procedure is outlined in 4.3 Alignment - final on page
21 and must be followed.
1. Be sure coupling halves are disconnected as previously instructed, except spider-insert type.
2. Tighten foundation bolts.
2.3 Alignment - initial
Model 3755 Installation, Operation, and Maintenance Manual 11

3. Tighten pump and driver hold-down bolts.
4. Check gap and angular misalignment, shaft axes concentric but not parallel.
1. Coupling other than spider-insert type.
The normal gap (distance between coupling halves) is 1/8". Check angular misalignment
by inserting a feeler or taper gauge at four points on the circumference of the coupling
halves at 90 degree intervals. See Figure 4: Checking angular alignment, except spider-
insert type on page 12. The unit will be in angular alignment when the measurements
show the coupling faces are the same distance apart at all points. Adjustment for gap and
for obtaining angular alignment is obtained be loosening the driver hold down bolts and
shifting or shimming driver as required. Tighten driver hold down bolts after adjustments
are made.
Figure 4: Checking angular alignment, except spider-insert type
2. Spider-insert type coupling.
The normal gap (distance of the space between coupling halves and the thickness of the
spider-insert) is 1/16". Check angular misalignment by using calipers at four points on the
circumference of the outer ends of the coupling hubs at 90 degree intervals. See Figure
5: Checking angular alignment, spider-insert type on page 13. The unit will be in angular
alignment when the measurements show the coupling hubs to be the same distance
apart at all points. Adjustment for obtaining the gap and angular alignment is obtained be
loosening the driver hold down bolts and shifting or shimming driver as required. Tighten
driver hold down bolts after adjustments are made.
2.3 Alignment - initial
12 Model 3755 Installation, Operation, and Maintenance Manual

Figure 5: Checking angular alignment, spider-insert type
5. Check parallel misalignment: shaft axes parallel but not concentric, by laying a straight edge
across both coupling rims at top, bottom and both sides. See Figure 6: Checking parallel align-
ment on page 13. This applies to both types of couplings.
The unit will be in horizontal alignment when the straight edge rests evenly on both halves of the
coupling at each side.
Figure 6: Checking parallel alignment
In order to secure vertical parallel alignment under actual operating conditions, the driver shaft
must be set higher or lower than the pump shaft to compensate for vertical expansion. A sug-
gested, approximate cold setting for motor driven pumps is outlined below:
1. When pumping cold liquids, or when pump bearings are being cooled, set the motor
shaft .006" below the pump shaft.
2. When pumping hot liquids (150º to 180ºF), and cooling is not used, set the motor and
pump shafts at same height.
Measure the difference in shaft heights by laying a straight edge across the shaft hubs
and checking with feelers.
2.3 Alignment - initial
Model 3755 Installation, Operation, and Maintenance Manual 13

Thin shim should be used under the driver feet to establish parallel alignment. (In some
instances, shims may be required under the pump feet).
6. Alignment in one direction may alter the alignment in another. Check through each alignment pro-
cedure after making any alignment alteration.
2.4 Piping - general
1. All piping must be supported independently of the pump. The piping should always "lineup" natu-
rally with the pump flanges. Never draw the piping into place by use of force at the flanged suc-
tion and discharge connections of the pump.
2. The piping, both suction and discharge, should be as short and direct as possible. Avoid all un-
necessary elbows, bends and fittings, as they increase the friction losses in the piping. The size
of pipe and fittings should be carefully selected and of sufficient size to keep the friction losses as
low as practical.
3. Piping must not be connected to the pump until the grout has thoroughly hardened and the foun-
dation bolts as well as driver and pump hold-down bolts have been tightened. See Section
2.7 Connection of piping on page 16.
4. When handling liquids at elevated temperatures, arrangements must be made for expansion
loops or expansion joints so that the linear expansion of the pipe will not cause the pumping unit
to be drawn out of alignment.
2.5 Install suction piping
1. General - properly installed suction piping is of extreme importance for trouble-free centrifugal pump
operation.
a) The suction pipe should be as large or larger than the pump suction.
b) lncreasers, if used, should be eccentric and preferably at the pump suction flange, sloping side
down.
c) A centrifugal pump should never be throttled on the suction side for capacity adjustment.
2. Installations With Pump Above Source of Supply - Suction Lift:
a) Keep suction pipe free from air pockets.
• No portion of piping should extend above
the pump suction nozzle.
b) All joints must be air tight.
c) The suction pipe should always be submerged into the source of supply as shown in Figure
7: Pipe submergence and entrance calculation on page 15.
d) A foot valve should only be used if necessary for priming, or, if the pump is to be used on inter-
mittent service and is required to hold its prime.
e) Suction strainers when used should have a net free area of at least three times the suction pipe
area.
3. Installations With Pump Below Source of Supply - Suction Head or Flooded Suction:
a) A gate valve should be installed in the suction line to permit closing the line for pump inspection
and maintenance.
b) The size of the entrance from the source of supply or minimum submergence over the entrance
should be calculated from the data shown in Figure 7: Pipe submergence and entrance calcula-
tion on page 15 for applicable condition to prevent air from being drawn into pipe.
2.4 Piping - general
14 Model 3755 Installation, Operation, and Maintenance Manual

Figure 7: Pipe submergence and entrance calculation
2.6 Piping - discharge
1. A gate valve and a check valve should be installed in the discharge line. The check valve should
be located between the gate valve and pump to permit inspection of the check valve. The gate
valve is required for priming, regulation of flow capacity and for inspection and maintenance of
the pump.
2. lncreasers, if used in discharge line, should be placed between the check valve and the pump.
2.6 Piping - discharge
Model 3755 Installation, Operation, and Maintenance Manual 15

2.7 Connection of piping
Connect suction and discharge piping. Rotate the pump shaft by hand several complete revolutions to be
sure that there is no binding and that all parts are free. Recheck alignment as described in Section Align-
ment - initial. If the connection of the piping causes unit to be out of alignment, correct piping to relieve
strain on the pump.
2.8 Check rotation
These pumps are built in right hand construction, i.e., clockwise rotation from driver end. The direction of
rotation is marked on the pump casing. Make sure that the driver rotates in the same direction. On elec-
tric motors, jog starting switch with coupling disconnected to be sure wiring is connected for correct rota-
tion. If the pump is run dry, the rotating parts within the pump may gall and seize to the stationary parts
as they depend on the liquid being pumped for lubrication.
2.9 Connection of coupling
Connect coupling, following instructions for the particular make of coupling furnished. The data is sup-
plied separately, giving complete instructions for connection, lubrication, alignment and maintenance.
Spider-insert type couplings are pre-assembled.
2.7 Connection of piping
16 Model 3755 Installation, Operation, and Maintenance Manual

3 Preparation for Operation
3.1 Pump bearings
1. Grease lubricated bearings
Sufficient lubricant is inserted at the factory for 2000 hours of operation.
2. Oil lubricated bearings
1. Remove adjustment assembly from oiler.
2. Adjust bars to Dim. A.
3. Lock in position.
4. Replace adjustment assembly in oiler.
Oil lubricated, and are not lubricated before leaving the factory.
A high quality turbine type oil, with rust and oxidation inhibitors, should be used. For the great majority of
operation conditions, oil temperature will run between 50 and 180°F. In this range an oil of 300 SSU vis-
cosity at 100°F. (approximately SAE 20) should be used.
If oil temperature exceeds 180°F for extended periods, use of cooling water in the frame cooling jacket is
recommended. For extreme conditions, refer to factory or a lubrication expert for a recommendation.
The constant level oiler (251) is found in the box of fittings shipped with the pump. Oiler needs to be set
to maintain proper oil level. Set the oiler to dimensions A and B as shown in Figure 8: Oiler setting on
page 17.
Oiler Size A B
#3 (4 oz.) 19/32" ½"
Figure 8: Oiler setting
Install the constant level oiler (251) in the frame (228A).
3 Preparation for Operation
Model 3755 Installation, Operation, and Maintenance Manual 17

Fill the oiler bottle with the proper grade of oil, and replace in the oiler. The frame is filled when an oil
level remains in the bottle. Several fillings of the bottle may be required. Never fill the frame through the
breather (113-A) or through the oiler without use of the bottle.
The oil capacities of the frames are: Groups S, 7 oz.; Group M, 12 oz.; Group L, 26 oz.. This does not
include any oil in the oiler.
3.2 Driver bearings
Check to be sure the driver bearings are properly lubricated.
3.3 Stuffing box
Packing
1. Stuffing box with packing rings:
These pumps are furnished with packed stuffing box. In the box of fittings accompanying the
pump will be found the stuffing box packing. The standard packing is white metal, graphite, long
fiber asbestos and is die formed to facilitate installation.
When installing the packing, twist the rings sideways just enough to get them around the shaft.
Figure 9: Stuffing box packing
NOTICE:
Do not attempt to pull rings straight out to get them over shaft.
Slide the lantern ring (105) out and away from the stuffing box. (Refer to 7.4 Sectional views,
parts list and interchangeability tables on page 29. Insert three rings of packing, staggering the
joints. The lantern ring should then be inserted in the stuffing box. When it is in its proper posi-
tion, it will be directly opposite the sealing inlet connection.
After the lantern ring is in place, insert two more rings of packing on Group S and M and three
more on Group L, staggering the joints. One extra ring is furnished in each set of packing. The
extra ring should be added as required.
Place one gland half in lower position in stuffing box. Slide cupped washers over studs and on
the bosses of the gland to hold gland halves together.
Place two gland nuts on the studs and draw up evenly but not tight.
2. Stuffing box with mechanical seal:
When mechanical seals are furnished, they are installed and adjusted at the factory. The seal in-
structions and seal drawing are shipped with the pump. These should be read for any special in-
structions and filed for future use in maintaining the pump.
If the pump has a single mechanical seal and is handling clear liquid, be sure circulating line from
casing to stuffing box is connected. It is sometimes removed to prevent damage during shipment.
This line ensures circulation of liquid around seal. If pump is handling abrasive solids which might
score the seal faces, the seal is usually flushed with clear compatible liquid from an outside
3.2 Driver bearings
18 Model 3755 Installation, Operation, and Maintenance Manual