GORMAN-RUPP 12C2-B User manual

OM‐00602‐03
April 7, 1980
Rev. D 11‐22‐17
GORMAN‐RUPP PUMPS
www.grpumps.com
e1980 Gorman‐Rupp Pumps Printed in U.S.A.
INSTALLATION, OPERATION,
AND MAINTENANCE MANUAL
WITH PARTS LIST
10 SERIES PUMP
MODEL
12C2‐B

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Gorman‐Rupp pump online at
www.grpumps.com
Valid serial number and e‐mail address required.
RECORD YOUR PUMP MODEL AND SERIAL NUMBER
Please record your pump model and serial number in the
spaces provided below. Your Gorman‐Rupp distributor
needs this information when you require parts or service.
Pump Model:
Serial Number:

TABLE OF CONTENTS
i
INTRODUCTION PAGE I - 1.................................................
SAFETY ‐ SECTION A PAGE A - 1............................................
INSTALLATION - SECTION B PAGE B - 1....................................
Pump Dimensions PAGE B - 1.....................................................
PREINSTALLATION INSPECTION PAGE B - 2............................................
POSITIONING PUMP PAGE B - 2.......................................................
Lifting PAGE B - 2.................................................................
Mounting PAGE B - 2.............................................................
Clearance PAGE B - 2.............................................................
SUCTION AND DISCHARGE PIPING PAGE B - 3.........................................
Materials PAGE B - 3..............................................................
Line Configuration PAGE B - 3......................................................
Connections to Pump PAGE B - 3..................................................
Gauges PAGE B - 3...............................................................
SUCTION LINES PAGE B - 3...........................................................
Fittings PAGE B - 3...............................................................
Strainers PAGE B - 3..............................................................
Sealing PAGE B - 3...............................................................
Suction Lines In Sumps PAGE B - 4.................................................
Suction Line Positioning PAGE B - 4................................................
DISCHARGE LINES PAGE B - 5........................................................
Siphoning PAGE B - 5.............................................................
Valves PAGE B - 5................................................................
Bypass Lines PAGE B - 5..........................................................
AUTOMATIC AIR RELEASE VALVE PAGE B - 6...........................................
Air Release Valve Installation PAGE B - 6............................................
ALIGNMENT PAGE B - 7..............................................................
Coupled Drives PAGE B - 8........................................................
V‐Belt Drives PAGE B - 8...........................................................
V‐BELT TENSIONING PAGE B - 9......................................................
General Rules of Tensioning PAGE B - 9.............................................
Tension Measurement PAGE B - 9..................................................
OPERATION - SECTION C PAGE C - 1......................................
PRIMING PAGE C - 1.................................................................
STARTING PAGE C - 1................................................................
Rotation PAGE C - 1..............................................................
OPERATION PAGE C - 2..............................................................
Lines With a Bypass PAGE C - 2....................................................
Lines Without a Bypass PAGE C - 2.................................................
Leakage PAGE C - 2..............................................................
Liquid Temperature And Overheating PAGE C - 2.....................................
Strainer Check PAGE C - 2.........................................................
Pump Vacuum Check PAGE C - 3..................................................
STOPPING PAGE C - 3................................................................
BEARING TEMPERATURE CHECK PAGE C - 3..........................................
Cold Weather Preservation PAGE C - 3..............................................

TABLE OF CONTENTS
(continued)
ii
TROUBLESHOOTING - SECTION D PAGE D - 1..............................
PREVENTIVE MAINTENANCE PAGE D - 3...............................................
PUMP MAINTENANCE AND REPAIR ‐ SECTION E PAGE E - 1.................
STANDARD PERFORMANCE CURVE PAGE E - 1........................................
PARTS LIST:
Pump Model PAGE E - 3..........................................................
PUMP AND SEAL DISASSEMBLY AND REASSEMBLY PAGE E - 4.........................
Back Cover Removal PAGE E - 4...................................................
Suction Check Valve Removal and Disassembly PAGE E - 4...........................
Pump Casing Removal PAGE E - 5.................................................
Impeller Removal PAGE E - 5......................................................
Seal Removal and Disassembly PAGE E - 5..........................................
Shaft and Bearing Removal and Disassembly PAGE E - 6.............................
Shaft and Bearing Reassembly and Installation PAGE E - 7............................
Seal Reassembly and Installation PAGE E - 8........................................
Impeller Installation And Adjustment PAGE E - 9......................................
Pump Casing Installation PAGE E - 9................................................
Back Cover Installation PAGE E - 9.................................................
Suction Check Valve Installation PAGE E - 10.........................................
Final Pump Assembly PAGE E - 10..................................................
LUBRICATION PAGE E - 10.............................................................
Seal Assembly PAGE E - 10.........................................................
Bearings PAGE E - 11..............................................................
Power Source PAGE E - 11.........................................................

10 SERIES OM-00602
PAGE I - 1INTRODUCTION
INTRODUCTION
Thank You for purchasing a Gorman‐Rupp pump.
Read this manual carefully to learn how to safely
install and operate your pump. Failure to do so
could result in personal injury or damage to the
pump.
This pump is a 10 Series, semi‐open impeller, self‐
priming centrifugal model with a suction check
valve. The pump is designed for handling most
non‐volatile, non‐flammable liquids containing
specified entrained solids. The basic material of
construction for wetted parts is gray iron, with a
ductile iron impeller and steel impeller shaft.
Because pump installations are seldom identical,
this manual cannot possibly provide detailed in
structions and precautions for every aspect of
each specific application. Therefore, it is the re
sponsibility of the owner/installer of the pump to
ensure that applications not addressed in this
manual are performed only after establishing that
neither operator safety nor pump integrity are com
promised by the installation. Pumps and related
equipment must be installed and operated ac
cording to all national, local and industry stan
dards.
For information or technical assistance on the pow
er source, contact the power source manufactur
er's local dealer or representative.
If there are any questions regarding the pump or
its application which are not covered in this man
ual or in other literature accompanying this unit,
please contact your Gorman‐Rupp distributor, or
The Gorman‐Rupp Company:
The Gorman‐Rupp Company
P.O. Box 1217
Mansfield, Ohio 44901-1217
Phone: [phone]
or:
Gorman‐Rupp of Canada Limited
70 Burwell Road
St. Thomas, Ontario N5P 3R7
Phone: [phone]
The following are used to alert maintenance per
sonnel to procedures which require special atten
tion, to those which could damage equipment, and
to those which could be dangerous to personnel:
Immediate hazards which WILL result in
severe personal injury or death. These
instructions describe the procedure re
quired and the injury which will result
from failure to follow the procedure.
Hazards or unsafe practices which
COULD result in severe personal injury
or death. These instructions describe
the procedure required and the injury
which could result from failure to follow
the procedure.
Hazards or unsafe practices which COULD
result in minor personal injury or product
or property damage. These instructions
describe the requirements and the possi
ble damage which could result from failure
to follow the procedure.
NOTE
Instructions to aid in installation, operation,and
maintenance, or which clarify a procedure.

10 SERIES OM-00602
PAGE A - 1SAFETY
SAFETY ‐ SECTION A
This information applies to 10 Series ba
sic pumps. Gorman‐Rupp has no con
trol over or particular knowledge of the
power source which will be used. Refer
to the manual accompanying the power
source before attempting to begin oper
ation.
This manual will alert personnel to
known procedures which require spe
cial attention, to those which could
damage equipment, and to those which
could be dangerous to personnel. How
ever, this manual cannot possibly antici
pate and provide detailed instructions
and precautions for every situation that
might occur during maintenance of the
unit. Therefore, it is the responsibility of
the owner/maintenance personnel to
ensure that only safe, established main
tenance procedures are used, and that
any procedures not addressed in this
manual are performed only after estab
lishing that neither personal safety nor
pump integrity are compromised by
such practices.
Before attempting to open or service the
pump:
1. Familiarize yourself with this man
ual.
2. Lock out or disconnect the power
source to ensure that the pump will
remain inoperative.
3. Allow the pump to completely cool
if overheated.
4. Check the temperature before
opening any covers, plates, or
plugs.
5. Close the suction and discharge
valves.
6. Vent the pump slowly and cau
tiously.
7. Drain the pump.
This pump is designed to handle most
non‐volatile, non‐flammable liquids
containing specified entrained solids.
Do not attempt to pump liquids for
which the pump has not been approved,
or which may damage the pump or en
danger personnel as a result of pump
failure.
Death or serious personal injury and
damage to the pump or components
can occur if proper lifting procedures
are not observed. Make certain that
hoists, chains, slings or cables are in
good working condition and of suffi
cient capacity and that they are posi
tioned so that loads will be balanced
and the pump or components will not be
damaged when lifting. Suction and dis
charge hoses and piping must be re
moved from the pump before lifting. Lift
the pump or component only as high as
necessary and keep personnel away
from suspended objects.
After the pump has been installed, make
certain that the pump and all piping or
hose connections are tight, properly
supported and secure before operation.

10 SERIESOM-00602
PAGE A - 2 SAFETY
Do not operate the pump without the
shields and/or guards in place over the
drive shaft, belts, and/or couplings, or
other rotating parts. Exposed rotating
parts can catch clothing, fingers, or
tools, causing severe injury to person
nel.
Do not operate the pump against a
closed discharge valve for long periods
of time. If operated against a closed dis
charge valve, pump components will
deteriorate, and the liquid could come
to a boil, build pressure, and cause the
pump casing to rupture or explode.
Overheated pumps can cause severe
burns and injuries. If overheating of the
pump occurs:
1. Stop the pump immediately.
2. Ventilate the area.
3. Allow the pump to completely cool.
4. Check the temperature before
opening any covers, plates,
gauges, or plugs.
5. Vent the pump slowly and cau
tiously.
6. Refer to instructions in this manual
before restarting the pump.
Do not remove plates, covers, gauges,
pipe plugs, or fittings from an over
heated pump. Vapor pressure within the
pump can cause parts being disen
gaged to be ejected with great force. Al
low the pump to completely cool before
servicing.
Never run this pump backwards. Be cer
tain that rotation is correct before fully
engaging the pump.
Pumps and related equipment must be in
stalled and operated according to all na
tional, local and industry standards.

10 SERIES OM-00602
PAGE B - 1INSTALLATION
INSTALLATION - SECTION B
Review all SAFETY information in Section A.
Since pump installations are seldom identical, this
section offers only general recommendations and
practices required to inspect, position, and ar
range the pump and piping.
Most of the information pertains to a standard
static lift application where the pump is positioned
above the free level of liquid to be pumped.
If installed in a flooded suction application where
the liquid is supplied to the pump under pressure,
some of the information such as mounting, line
configuration, and priming must be tailored to the
specific application. This pump is equipped with a
Gorman‐Rupp double grease lubricated seal,
therefore the maximum incoming pressure must
be limited to 10 p.s.i.
For further assistance, contact your Gorman‐Rupp
distributor or the Gorman‐Rupp Company.
Pump Dimensions
See Figure 1 for the approximate physical dimen
sions of this pump.
OUTLINE DRAWING
Figure B-1. Pump Model 12C2-B

OM-00602 10 SERIES
PAGE B - 2 INSTALLATION
PREINSTALLATION INSPECTION
The pump assembly was inspected and tested be
fore shipment from the factory. Before installation,
inspect the pump for damage which may have oc
curred during shipment. Check as follows:
a. Inspect the pump for cracks, dents, damaged
threads, and other obvious damage.
b. Check for and tighten loose attaching hard
ware. Since gaskets tend to shrink after dry
ing, check for loose hardware at mating sur
faces.
c. Carefully read all tags, decals, and markings
on the pump assembly, and perform all duties
indicated.
Only operate this pump in the direction in
dicated by the arrow on the pump body
and on the accompanying decal. Other
wise, the impeller could become loosened
from the shaft and seriously damage the
pump. Refer to Rotation in OPERATION,
Section C.
d. Check levels and lubricate as necessary. Re
fer to LUBRICATION in the MAINTENANCE
AND REPAIR section of this manual and per
form duties as instructed.
e. If the pump has been stored for more than 12
months, some of the components or lubri
cants may have exceeded their maximum
shelf life. These must be inspected or re
placed to ensure maximum pump service.
If the maximum shelf life has been exceeded, or if
anything appears to be abnormal, contact your
Gorman‐Rupp distributor or the factory to deter
mine the repair or updating policy. Do not put the
pump into service until appropriate action has
been taken.
POSITIONING PUMP
Death or serious personal injury and
damage to the pump or components
can occur if proper lifting procedures
are not observed. Make certain that
hoists, chains, slings or cables are in
good working condition and of suffi
cient capacity and that they are posi
tioned so that loads will be balanced
and the pump or components will not be
damaged when lifting. Suction and dis
charge hoses and piping must be re
moved from the pump before lifting. Lift
the pump or component only as high as
necessary and keep personnel away
from suspended objects.
Lifting
Pump unit weights will vary depending on the
mounting and drive provided. Check the shipping
tag on the unit packaging for the actual weight, and
use lifting equipment with appropriate capacity.
Drain the pump and remove all customer‐installed
equipment such as suction and discharge hoses
or piping before attempting to lift existing, installed
units.
Mounting
Locate the pump in an accessible place as close as
practical to the liquid being pumped. Level mount
ing is essential for proper operation.
The pump may have to be supported or shimmed
to provide for level operation or to eliminate vibra
tion.
Clearance
It is recommended that 18 inches (457 mm) of
clearance be provided in front of the back cover to
permit removal of the cover and easy access to the
pump interior. A minimum clearance of 6 inches
(152,4 mm) must be maintained to permit removal
of the cover.

10 SERIES OM-00602
PAGE B - 3INSTALLATION
SUCTION AND DISCHARGE PIPING
Pump performance is adversely effected by in
creased suction lift, discharge elevation, and fric
tion losses. See the performance curve on Page
E-1 to be sure your overall application allows
pump to operate within the safe operation range.
Materials
Either pipe or hose maybe used for suction and
discharge lines; however, the materials must be
compatible with the liquid being pumped. If hose is
used in suction lines, it must be the rigid‐wall, rein
forced type to prevent collapse under suction. Us
ing piping couplings in suction lines is not recom
mended.
Line Configuration
Keep suction and discharge lines as straight as
possible to minimize friction losses. Make mini
mum use of elbows and fittings, which substan
tially increase friction loss. If elbows are necessary,
use the long‐radius type to minimize friction loss.
Connections to Pump
Before tightening a connecting flange, align it ex
actly with the pump port. Never pull a pipe line into
place by tightening the flange bolts and/or cou
plings.
Lines near the pump must be independently sup
ported to avoid strain on the pump which could
cause excessive vibration, decreased bearing life,
and increased shaft and seal wear. If hose‐type
lines are used, they should have adequate support
to secure them when filled with liquid and under
pressure.
Gauges
Most pumps are drilled and tapped for installing
discharge pressure and vacuum suction gauges.
If these gauges are desired for pumps that are not
tapped, drill and tap the suction and discharge
lines not less than 18 inches (457,2 mm) from the
suction and discharge ports and install the lines.
Installation closer to the pump may result in erratic
readings.
SUCTION LINES
To avoid air pockets which could affect pump prim
ing, the suction line must be as short and direct as
possible. When operation involves a suction lift, the
line must always slope upward to the pump from
the source of the liquid being pumped; if the line
slopes down to the pump at any point along the
suction run, air pockets will be created.
Fittings
Suction lines should be the same size as the pump
inlet. If reducers are used in suction lines, they
should be the eccentric type, and should be in
stalled with the flat part of the reducers uppermost
to avoid creating air pockets. Valves are not nor
mally used in suction lines, but if a valve is used,
install it with the stem horizontal to avoid air pock
ets.
Strainers
If a strainer is furnished with the pump, be certain
to use it; any spherical solids which pass through a
strainer furnished with the pump will also pass
through the pump itself.
If a strainer is not furnished with the pump, but is
installed by the pump user, make certain that the
total area of the openings in the strainer is at least
three or four times the cross section of the suction
line, and that the openings will not permit passage
of solids larger than the solids handling capability
of the pump.
This pump is designed to handle up to 1-1/8 inch
(28,6 mm) diameter spherical solids.
Sealing
Since even a slight leak will affect priming, head,
and capacity, especially when operating with a
high suction lift, all connections in the suction line
should be sealed with pipe dope to ensure an air
tight seal. Follow the sealant manufacturer's rec
ommendations when selecting and applying the
pipe dope. The pipe dope should be compatible
with the liquid being pumped.

OM-00602 10 SERIES
PAGE B - 4 INSTALLATION
Suction Lines In Sumps
If a single suction line is installed in a sump, it
should be positioned away from the wall of the
sump at a distance equal to 1‐1/2 times the diame
ter of the suction line.
If there is a liquid flow from an open pipe into the
sump, the flow should be kept away from the suc
tion inlet because the inflow will carry air down into
the sump, and air entering the suction line will re
duce pump efficiency.
If it is necessary to position inflow close to the suc
tion inlet, install a baffle between the inflow and the
suction inlet at a distance 1‐1/2 times the diameter
of the suction pipe. The baffle will allow entrained
air to escape from the liquid before it is drawn into
the suction inlet.
If two suction lines are installed in a single sump,
the flow paths may interact, reducing the efficiency
of one or both pumps. To avoid this, position the
suction inlets so that they are separated by a dis
tance equal to at least 3 times the diameter of the
suction pipe.
Suction Line Positioning
The depth of submergence of the suction line is
critical to efficient pump operation. Figure 2 shows
recommended minimum submergence vs. veloc
ity.
NOTE
The pipe submergence required may be reduced
by installing a standard pipe increaser fitting at the
end of the suction line. The larger opening size will
reduce the inlet velocity. Calculate the required
submergence using the following formula based
on the increased opening size (area or diameter).
Figure B-2. Recommended Minimum Suction Line Submergence vs. Velocity

10 SERIES OM-00602
PAGE B - 5INSTALLATION
DISCHARGE LINES
Siphoning
Do not terminate the discharge line at a level lower
than that of the liquid being pumped unless a si
phon breaker is used in the line. Otherwise, a si
phoning action causing damage to the pump
could result.
Valves
If a throttling valve is desired in the discharge line,
use a valve as large as the largest pipe to minimize
friction losses. Never install a throttling valve in a
suction line.
With high discharge heads, it is recommended that
a throttling valve and a system check valve be in
stalled in the discharge line to protect the pump
from excessive shock pressure and reverse rota
tion when it is stopped.
If the application involves a high discharge
head, gradually close the discharge
throttling valve before stopping the pump.
Bypass Lines
Self‐priming pumps are not air compressors. Dur
ing the priming cycle, air from the suction line must
be vented to atmosphere on the discharge side. If
the discharge line is open, this air will be vented
through the discharge. However, if a check valve
has been installed in the discharge line, the dis
charge side of the pump must be opened to atmos
pheric pressure through a bypass line installed be
tween the pump discharge and the check valve. A
self‐priming centrifugal pump will not prime if
there is sufficient static liquid head to hold the dis
charge check valve closed.
NOTE
The bypass line should be sized so that it does not
affect pump discharge capacity; however, the by
pass line should be at least 1 inch (25,4 mm) in di
ameter to minimize the chance of plugging.
In low discharge head applications (less than 30
feet (9,1 m)), it is recommended that the bypass
line be run back to the wet well, and located 6
inches below the water level or cut‐off point of the
low level pump. In some installations, this bypass
outline may be terminated with a six‐to‐eight foot
(1,8 to 2,4 m) length of 1‐1/4 inch (31,8 mm) I.D.
smooth‐bore hose; air and liquid vented during
the priming process will then agitate the hose and
break up any solids, grease, or other substances
likely to cause clogging.
A bypass line that is returned to a wet well
must be secured against being drawn into
the pump suction inlet.
It is also recommended that pipe unions be in
stalled at each 90_elbow in a bypass line to ease
disassembly and maintenance.
In high discharge head applications (more than
30 feet (9,1 m), an excessive amount of liquid may
be bypassed and forced back to the wet well under
the full working pressure of the pump; this will re
duce overall pumping efficiency. Therefore, it is
recommended that a Gorman‐Rupp Automatic
Air Release Valve be installed in the bypass line.
Gorman‐Rupp Automatic Air Release Valves are
reliable, and require minimum maintenance. See
Automatic Air Release Valves in this section for
installation and theory of operation of the Auto
matic Air Release Valve. Consult your Gorman‐
Rupp distributor, or contact the Gorman‐Rupp
Company for selection of an Automatic Air Release
Valve to fit your application.
Except in certain specific applications (to
prevent flooding during service of an auto
matic air release valve in a below‐ground
lift station), if a manual shut‐off valve is in
stalled anywhere in a bypass line, it must
be a full‐opening, ball‐type valve to pre
vent plugging by solids.

OM-00602 10 SERIES
PAGE B - 6 INSTALLATION
A manual shut‐off valve should not be
installed in any bypass line. A manual
shut‐off valve may inadvertently be left
closed during operation. A pump which
has lost prime may continue to operate
without reaching prime, causing dan
gerous overheating and possible explo
sive rupture of the pump casing. Per
sonnel could be severely injured.
Allow an over‐heated pump to com
pletely cool before servicing. Do not re
move plates, covers, gauges, or fittings
from an over‐heated pump. Liquid with
in the pump can reach boiling tempera
tures, and vapor pressure within the
pump can cause parts being disen
gaged to be ejected with great force. Af
ter the pump completely cools, drain the
liquid from the pump by removing the
casing drain plug. Use caution when re
moving the plug to prevent injury to per
sonnel from hot liquid.
AUTOMATIC AIR RELEASE VALVE
When properly installed, a Gorman‐Rupp Auto
matic Air Release Valve will permit air to escape
through the bypass line and then close automati
cally when the pump is fully primed and pumping
at full capacity.
Some leakage (1 to 5 gallons [3.8 to 19
liters] per minute) will occur when the
valve is fully closed. Be sure the bypass
line is directed back to the wet well or
tank to prevent hazardous spills.
Consult the manual accompanying the Air Release
Valve for additional information on valve installation
and performance.
Air Release Valve Installation
The Automatic Air Release Valve must be inde
pendently mounted in a horizontal position be
tween the pump discharge port and the inlet side of
the discharge check valve (see Figure 3). The inlet
opening in the Air Release Valve is equipped with
standard 1‐inch NPT pipe threads.

10 SERIES OM-00602
PAGE B - 7INSTALLATION
DISCHARGE PIPE
DISCHARGE
CHECK VALVE
PUMP DISCHARGE
SELF‐PRIMING
CENTRIFUGAL
PUMP
SUCTION
LINE
SUPPORT
BRACKET
CLEAN‐OUT
COVER
INSTALL AIR RELEASE VALVE
IN HORIZONTAL POSITION
90_LONG
RADIUS
ELBOW
WET WELL
OR SUMP
BLEED LINE 1”
(25,4 MM) DIA. MIN.
(CUSTOMER FUR
NISHED) DO NOT EX
TEND BELOW PUMP
OFF LIQUID LEVEL
Figure 3. Typical Automatic Air Release Valve Installation
Connect the valve outlet to a bleed line which
slopes back to the wet well or sump. The bleed line
must be the same size as the outlet opening or
larger, depending on which Air Release Valve is be
ing used. If piping is used for the bleed line, avoid
the use of elbows whenever possible.
NOTE
For multiple pump installations, it is recommended
that each Air Release Valve be fitted with an inde
pendent bleeder line directed back to the wet well.
If multiple Air Release Valves are installed in a sys
tem, do not direct bleeder lines to a common mani
fold pipe. Contact your Gorman‐Rupp distributor or
the Gorman‐Rupp Company for information about
installation of an Automatic Air Release Valve for
your specific application.
ALIGNMENT
The alignment of the pump and its power source is
critical for trouble‐free mechanical operation. In
either a flexible coupling or V‐belt driven system,
the driver and pump must be mounted so that their
shafts are aligned with and parallel to each other. It
is imperative that alignment be checked after the
pump and piping are installed, and before opera
tion.
NOTE
Check Rotation, Section C, before final alignment
of the pump.
When mounted at the Gorman‐Rupp factory, driver
and pump are aligned before shipment. Misalign
ment will occur in transit and handling. Pumps
must be checked and realigned before operation.
Before checking alignment, tighten the foundation
bolts. The pump casing feet and/or pedestal feet,
and the driver mounting bolts should also be tightly
secured.
When checking alignment, disconnect
the power source to ensure that the
pump will remain inoperative.

OM-00602 10 SERIES
PAGE B - 8 INSTALLATION
Adjusting the alignment in one direction
may alter the alignment in another direc
tion. check each procedure after altering
alignment.
Coupled Drives
When using couplings, the axis of the power
source must be aligned to the axis of the pump
shaft in both the horizontal and vertical planes.
Most couplings require a specific gap or clearance
between the driving and the driven shafts. Refer to
the coupling manufacturer's service literature.
Align spider insert type couplings by using calipers
to measure the dimensions on the circumference
of the outer ends of the coupling hub every 90 de
grees. The coupling is in alignment when the hub
ends are the same distance apart at all points (see
Figure 4A).
Figure 4A. Aligning Spider Type Couplings
Figure 4B. Aligning Non‐Spider Type
Couplings
Align non‐spider type couplings by using a feeler
gauge or taper gauge between the coupling halves
every 90 degrees. The coupling is in alignment
when the hubs are the same distance apart at all
points (see Figure 4B).
Check parallel adjustment by laying a straightedge
across both coupling rims at the top, bottom, and
side. When the straightedge rests evenly on both
halves of the coupling, the coupling is in horizontal
parallel alignment. If the coupling is misaligned,
use a feeler gauge between the coupling and the
straightedge to measure the amount of misalign
ment.
V‐Belt Drives
When using V‐belt drives, the power source and
the pump must be parallel. Use a straightedge
along the sides of the pulleys to ensure that the pul
leys are properly aligned (see Figure 4C). In drive
systems using two or more belts, make certain that
the belts are a matched set; unmatched sets will
cause accelerated belt wear.
MISALIGNED:
SHAFTS
NOT PARALLEL
MISALIGNED:
SHAFTS
NOT IN LINE
ALIGNED: SHAFTS
PARALLEL AND
SHEAVES IN LINE
Figure 4C. Alignment of V‐Belt Driven Pumps
Tighten the belts in accordance with the belt manu
facturer's instructions. If the belts are too loose,
they will slip; if the belts are too tight, there will be
excessive power loss and possible bearing failure.
Select pulleys that will match the proper speed ra
tio; overspeeding the pump may damage both
pump and power source.
Do not operate the pump without the
shields and/or guards in place over the
drive shaft, belts, and/or couplings, or
other rotating parts. Exposed rotating

10 SERIES OM-00602
PAGE B - 9INSTALLATION
parts can catch clothing, fingers, or
tools, causing severe injury to person
nel.
V‐BELT TENSIONING
General Rules of Tensioning
For new v‐belts, check the tension after 5, 20 and
50 hours of operation and re‐tension as required
(see the following procedure for measuring belt
tension). Thereafter, check and re‐tension if re
quired monthly or at 500 hour intervals, whichever
comes first.
Ideal v‐belt tension is the lowest tension at which
the belt will not slip under peak load conditions. Do
not over‐tension v‐belts. Over‐tensioning will short
en both v‐belt and bearing life. Under‐tensioning
will cause belt slippage. Always keep belts free
from dirt, grease, oil and other foreign material
which may cause slippage.
Tension Measurement
Correct v‐belt tension can be achieved using a v‐
belt tension tester and Table 1 or 2. Use the tables
to find the v‐belt size (cross‐section), the smallest
sheave diameter, the belt type for your application.
The corresponding deflection force required for
new or used belts is shown opposite the RPM
range of the pump.
Belt Span
Deflection
Figure 5. Belt Tension Measurement
The ratio of deflection to belt span is 1:64 for both
ASA and metric units. Therefore, a belt with a span
of 64 inches would require a deflection of 1 inch at
the force shown on the Tables for your particular
application.
For example, if the span as measured in Figure 5 is
32 inches (813 mm), the v‐belt cross‐section is C,
the smallest sheave diameter is 8 inches, the pump
speed is 1250 RPM, and the belts are uncogged
Yy‐T type, then 11.5 lbs. of force on the tensioner
should show 1/2‐inch (12,7 mm) of deflection.
A tension tester is available as an option from Gor
man‐Rupp (P/N 29513-001). Other tension test
ers are available from your local belt/sheave dis
tributor, and work on a similar principal.
To use the Gorman‐Rupp tensioner, measure the
belt span as shown in Figure 5. Position the bottom
of the large O‐ring on the span scale of the tension
er at the measured belt span. Set the small O‐ring
on the deflection force scale to zero.
Place the tension tester squarely on the belt at the
center of the belt span. Apply force on the plunger,
perpendicular to the belt span, until the bottom of
the large O‐ring is even with the top of the next belt,
or with the bottom of a straight edge laid across the
sheaves.
Read the force applied from the bottom of the small
O‐ring on the deflection force scale. Compare this
force with the value shown in Table 1 or 2 and ad
just the tension accordingly. Note that the tension
for new belts is higher than that for used belts to
allow for expected belt stretching. Do not over‐ten
sion used belts to the higher deflection forces
shown for new belts.

OM-00602 10 SERIES
PAGE B - 10 INSTALLATION
Table 1. Sheave Diameter (Inches)
Deflection Force (Lbs.)
Cross
Section
Smallest
Sheave
Diameter
Range R.P.M.
Range
Used
Belt
New
Belt
Used
Belt
New
Belt
Belt Deflection Force
Uncogged
Hy‐T Belts &
Uncogged
Hy‐T Torque
Team
Cogged
Torque‐Flex
& Machined
Edge torque
Team Belts
A,AX
3.0 ‐ 3.6 1000‐2500
2501‐4000
3.7
2.8
5.5
4.2
4.1
3.4
6.1
5.0
3.8 ‐ 4.8 1000‐2500
2501‐4000
4.5
3.8
6.8
5.7
5.0
4.3 7.4
6.4
5.0 ‐ 7.0 1000‐2500
2501‐4000
5.4
4.7
8.0
7.0
5.7
5.1
9.4
7.4
B,BX
3.4 ‐ 4.2 860‐2500
2501‐4000
4.9
4.2
7.2
6.2
4.4 ‐ 5.6 860‐2500
2501‐4000
5.3
4.5
7.9
6.7
7.1
7.1
10.5
9.1
5.8 ‐ 8.6 860‐2500
2501‐4000
6.3
6.0
9.4
8.9
8.5
7.3
12.6
10.9
C,CX
7.0 ‐ 9.0 500‐1740
1741‐3000
11.5
9.4
17.0
13.8
14.7
11.9
21.8
17.5
9.5 ‐ 16.0 500‐1740
1741‐3000
14.1
12.5
21.0
18.5
15.9
14.6
23.5
21.6
D
12.0 ‐ 16.0 200‐850
851‐1500
11.5
9.4
17.0
13.8
14.7
11.9
21.8
17.5
18.0 ‐ 20.0 200‐850
851‐1500
30.4
25.6
45.2
38.0
3V,
3VX
2.2 ‐ 2.4 1000‐2500
2501‐4000
3.3
2.9
4.9
4.3
2.65 ‐ 3.65 1000‐2500
2501‐4000
3.6
3.0
5.1
4.4
4.2
3.8
6.2
5.6
4.12 ‐ 6.90 1000‐2500
2501‐4000
4.9
4.4
7.3
6.6
5.3
4.9
7.9
7.3
5V,
5VX
4.4 ‐ 6.7
500‐1749
1750‐3000
3001‐4000
10.2
8.8
5.6
15.2
13.2
8.5
7.1 ‐ 10.9 500‐1740
1741‐3000
12.7
11.2
18.9
16.7
14.8
13.7
22.1
20.1
11.8 ‐ 16.0 500‐1740
1741‐3000
15.5
14.6
23.4
21.8
17.1
16.8
25.5
25.0
8V
12.5 ‐ 17.0 200‐850
851‐1500
33.0
26.8
49.3
39.9
200‐850
851‐1500
39.6
35.3
59.2
52.7
18.0 ‐ 22.4
Table 2. Sheave Diameter (Millimeters)
Deflection Force (KG.)
Cross
Section
Smallest
Sheave
Diameter
Range R.P.M.
Range
Used
Belt
New
Belt
Used
Belt
New
Belt
Belt Deflection Force
Uncogged
Hy‐T Belts &
Uncogged
Hy‐T Torque
Team
Cogged
Torque‐Flex
& Machined
Edge torque
Team Belts
A,AX
75 ‐ 90 1000‐2500
2501‐4000
1.7
1.3
2.5
1.9
1.9
1.5
2.8
2.3
91 ‐ 120 1000‐2500
2501‐4000
2.0
1.7
3.1
2.6
2.3
2.0 3.4
2.9
125 ‐ 175 1000‐2500
2501‐4000
2.4
2.1
3.6
3.2
2.6
2.3
4.3
3.4
B,BX
85 ‐ 105 860‐2500
2501‐4000
2.2
1.9
3.3
2.8
106 ‐ 140 860‐2500
2501‐4000
2.4
2.0
3.6
3.0
3.2
3.2
4.8
4.1
141 ‐ 220 860‐2500
2501‐4000
2.9
2.7
4.3
4.0
3.9
3.3
5.7
4.9
C,CX
175 ‐ 230 500‐1740
1741‐3000
5.2
4.3
7.7
6.3
6.7
5.4
9.9
7.9
231 ‐ 400 500‐1740
1741‐3000
6.4
5.7
9.5
8.4
7.2
6.6
10.7
9.8
D
305 ‐ 400 200‐850
851‐1500
11.3
9.6
16.8
14.2
401 ‐ 510 200‐850
851‐1500
13.8
11.6
20.5
17.2
3V,
3VX
55 ‐ 60 1000‐2500
2501‐4000
1.5
1.3
2.2
2.0
61 ‐ 90 1000‐2500
2501‐4000
1.6
1.4
2.3
2.0
1.9
1.7
2.8
2.5
91 ‐ 175 1000‐2500
2501‐4000
2.2
2.0
3.3
3.0
2.4
2.2
3.6
3.3
5V,
5VX
110 ‐ 170
500‐1749
1750‐3000
3001‐4000
4.6
4.0
2.5
6.9
6.0
3.9
171 ‐ 1275 500‐1740
1741‐3000
5.8
5.1
8.6
7.6
6.7
6.2
10.0
9.1
276 ‐ 400 500‐1740
1741‐3000
7.0
6.6
10.6
9.9
7.8
7.6
11.6
11.3
8V
315 ‐ 430 200‐850
851‐1500
15.0
12.2
22.4
18.1
200‐850
851‐1500
18.0
16.0
26.8
23.9
431 ‐ 570

OM-00602
10 SERIES
OPERATION PAGE C - 1
OPERATION - SECTION C
Review all SAFETY information in Section A.
Follow the instructions on all tags, labels and
decals attached to the pump.
This pump is designed to handle most
non‐volatile, non‐flammable liquids
containing specified entrained solids.
Do not attempt to pump liquids which
may damage the pump or endanger per
sonnel as a result of pump failure.
Pump speed and operating condition
points must be within the continuous per
formance range shown on the curve (see
Section E, Page 1).
PRIMING
Install the pump and piping as described in IN
STALLATION. Make sure that the piping connec
tions are tight, and that the pump is securely
mounted. Check that the pump is properly lubri
cated (see LUBRICATION in MAINTENANCE
AND REPAIR).
This pump is self‐priming, but the pump should
never be operated unless there is liquid in the
pump casing.
Never operate this pump unless there is
liquid in the pump casing. The pump will
not prime when dry. Extended operation of
a dry pump will destroy the seal assembly.
Add liquid to the pump casing when:
1. The pump is being put into service for the
first time.
2. The pump has not been used for a consider
able length of time.
3. The liquid in the pump casing has evapo
rated.
Once the pump casing has been filled, the pump
will prime and reprime as necessary.
After filling the pump casing, reinstall
and tighten the fill plug. Do not attempt
to operate the pump unless all connect
ing piping is securely installed. Other
wise, liquid in the pump forced out un
der pressure could cause injury to per
sonnel.
To fill the pump, remove the pump casing fill cover
or fill plug in the top of the casing, and add clean
liquid until the casing is filled. Replace the fill cover
or fill plug before operating the pump.
STARTING
Consult the operations manual furnished with the
power source.
Rotation
The correct direction of pump rotation is counter
clockwise when facing the impeller. If the pump is
operated in the wrong direction, the impeller could
become loosened from the shaft and seriously
damage the pump.
Only operate this pump in the direction in
dicated by the arrow on the pump body
and on the accompanying decal. Other
wise, the impeller could become loosened
from the shaft and seriously damage the
pump.

OM-00602 10 SERIES
OPERATIONPAGE C - 2
Consult the operating manual furnished with the
power source before attempting to start the power
source.
If an electric motor is used to drive the pump, re
move V‐belts, couplings, or otherwise disconnect
the pump from the motor before checking motor
rotation. Operate the motor independently while
observing the direction of the motor shaft, or cool
ing fan.
If rotation is incorrect on a three‐phase motor, have
a qualified electrician interchange any two of the
three phase wires to change direction. If rotation is
incorrect on a single‐phase motor, consult the lit
erature supplied with the motor for specific instruc
tions.
OPERATION
Lines With a Bypass
Close the discharge throttling valve (if so
equipped) so that the pump will not have to prime
against the weight of the liquid in the discharge
line. Air from the suction line will be discharged
through the bypass line back to the wet well during
the priming cycle. When the pump is fully primed
and liquid is flowing steadily from the bypass line,
open the discharge throttling valve. Liquid will then
continue to circulate through the bypass line while
the pump is in operation.
Lines Without a Bypass
Open all valves in the discharge line and start the
engine. Priming is indicated by a positive reading
on the discharge pressure gauge or by a quieter
operation. The pump may not prime immediately
because the suction line must first fill with liquid. If
the pump fails to prime within five minutes, stop it
and check the suction line for leaks.
After the pump has been primed, partially close the
discharge line throttling valve in order to fill the line
slowly and guard against excessive shock pres
sure which could damage pipe ends, gaskets,
sprinkler heads, and any other fixtures connected
to the line. When the discharge line is completely
filled, adjust the throttling valve to the required flow
rate.
Leakage
No leakage should be visible at pump mating sur
faces, or at pump connections or fittings. Keep all
line connections and fittings tight to maintain maxi
mum pump efficiency.
Liquid Temperature And Overheating
The maximum liquid temperature for this pump is
110_F (43_C). Do not apply it at a higher operating
temperature.
Overheating can occur if operated with the valves
in the suction or discharge lines closed. Operating
against closed valves could bring the liquid to a
boil, build pressure, and cause the pump to rup
ture or explode. If overheating occurs, stop the
pump and allow it to completely cool before servic
ing it. Refill the pump casing with cool liquid.
Do not remove plates, covers, gauges,
pipe plugs, or fittings from an over
heated pump. Vapor pressure within the
pump can cause parts being disen
gaged to be ejected with great force. Al
low the pump to completely cool before
servicing.
Strainer Check
If a suction strainer has been shipped with the
pump or installed by the user, check the strainer
regularly, and clean it as necessary. The strainer
should also be checked if pump flow rate begins to
drop. If a vacuum suction gauge has been in
stalled, monitor and record the readings regularly
to detect strainer blockage.
Never introduce air or steam pressure into the
pump casing or piping to remove a blockage. This
could result in personal injury or damage to the
equipment. If backflushing is absolutely neces
sary, liquid pressure must be limited to 50% of the
maximum permissible operating pressure shown
on the pump performance curve (see Section E,
Page 1).

OM-00602
10 SERIES
OPERATION PAGE C - 3
Pump Vacuum Check
With the pump inoperative, install a vacuum gauge
in the system, using pipe dope on the threads.
Block the suction line and start the pump. At oper
ating speed the pump should pull a vacuum of 20
inches (508,0 mm) or more of mercury. If it does
not, check for air leaks in the seal, gasket, or dis
charge valve.
Open the suction line, and read the vacuum gauge
with the pump primed and at operation speed.
Shut off the pump. The vacuum gauge reading will
immediately drop proportionate to static suction
lift, and should then stabilize. If the vacuum reading
falls off rapidly after stabilization, an air leak exists.
Before checking for the source of the leak, check
the point of installation of the vacuum gauge.
STOPPING
Never halt the flow of liquid suddenly. If the liquid
being pumped is stopped abruptly, damaging
shock waves can be transmitted to the pump and
piping system. Close all connecting valves slowly.
If the application involves a high discharge
head, gradually close the discharge
throttling valve before stopping the pump.
After stopping the pump, lock out or disconnect
the power source to ensure that the pump will re
main inoperative.
BEARING TEMPERATURE CHECK
Bearings normally run at higher than ambient tem
peratures because of heat generated by friction.
Temperatures up to 160_F (71_C) are considered
normal for bearings, and they can operate safely to
at least 180_F (82_C).
Checking bearing temperatures by hand is inaccu
rate. Bearing temperatures can be measured ac
curately by placing a contact‐type thermometer
against the housing. Record this temperature for
future reference.
A sudden increase in bearing temperatures is a
warning that the bearings are at the point of failing
to operate properly. Make certain that the bearing
lubricant is of the proper viscosity and at the cor
rect level (see LUBRICATION in Section E). Bear
ing overheating can also be caused by shaft
misalignment and/or excessive vibration.
When pumps are first started, the bearings may
seem to run at temperatures above normal. Con
tinued operation should bring the temperatures
down to normal levels.
Cold Weather Preservation
In below freezing conditions, drain the pump to
prevent damage from freezing. Also, clean out any
solids by flushing with a hose. Operate the pump
for approximately one minute; this will remove any
remaining liquid that could freeze the pump rotat
ing parts. If the pump will be idle for more than a
few hours, or if it has been pumping liquids con
taining a large amount of solids, drain the pump,
and flush it thoroughly with clean water. To prevent
large solids from clogging the drain port and pre
venting the pump from completely draining, insert
a rod or stiff wire in the drain port, and agitate the
liquid during the draining process. Clean out any
remaining solids by flushing with a hose.