GORMAN-RUPP PUMPS 12B20-B/S1 Application guide

OM-06599-01
October 17, 2012
K
THE GORMAN‐RUPP COMPANY DMANSFIELD, OHIO
www.grpumps.com
GORMAN‐RUPP OF CANADA LIMITED DST. THOMAS, ONTARIO, CANADA Printed in U.S.A.
e2012 The Gorman‐Rupp Company
INSTALLATION, OPERATION,
AND MAINTENANCE MANUAL
WITH PARTS LIST
10 SERIES PUMP
MODEL
12B20-B /S1

Register your new
Gorman‐Rupp pump online at
www.grpumps.com/register.
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 - 1............................................
POSITIONING PUMP PAGE B - 2.......................................................
Lifting PAGE B - 2.................................................................
Mounting PAGE B - 2.............................................................
Clearance PAGE B - 2.............................................................
SUCTION AND DISCHARGE PIPING PAGE B - 2.........................................
Materials PAGE B - 2..............................................................
Line Configuration PAGE B - 2......................................................
Connections to Pump PAGE B - 2..................................................
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 - 3.................................................
Suction Line Positioning PAGE B - 3................................................
DISCHARGE LINES PAGE B - 4........................................................
Siphoning PAGE B - 4.............................................................
Valves PAGE B - 4................................................................
Bypass Lines PAGE B - 4..........................................................
AUTOMATIC AIR RELEASE VALVE PAGE B - 5...........................................
ALIGNMENT PAGE B - 6..............................................................
Coupled Drives PAGE B - 6........................................................
V‐Belt Drives PAGE B - 7...........................................................
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 - 2..................................................
STOPPING PAGE C - 3................................................................
Cold Weather Preservation PAGE C - 3..............................................
BEARING TEMPERATURE CHECK PAGE C - 3..........................................
TROUBLESHOOTING - SECTION D PAGE D - 1..............................
PREVENTIVE MAINTENANCE PAGE D - 3...............................................

TABLE OF CONTENTS
(continued)
ii
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.........................
Suction Check Valve Removal and Disassembly PAGE E - 4...........................
Back Cover Removal PAGE E - 4...................................................
Pump Casing Removal PAGE E - 4.................................................
Impeller Removal PAGE E - 5......................................................
Seal Removal and Disassembly PAGE E - 5..........................................
Shaft and Bearing Removal and Disassembly PAGE E - 5.............................
Shaft and Bearing Reassembly and Installation PAGE E - 6............................
Seal Reassembly and Installation PAGE E - 7........................................
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 - 10..............................................................
Power Source PAGE E - 10.........................................................

10 SERIES OM-06599
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 cast iron, with duc
tile iron impeller.
This manual will alert personnel to known proce
dures which require special attention, to those
which could damage equipment, and to those
which could be dangerous to personnel. However,
this manual cannot possibly anticipate and provide
detailed precautions for every situation that might
occur during maintenance of the unit. Therefore, it
is the responsibility of the owner/maintenance per
sonnel to ensure that only safe, established main
tenance procedures are used, and that any proce
dures not addressed in this manual are performed
only after establishing that neither personal safety
nor pump integrity are compromised by such prac
tices.
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-06599
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.
Because pump installations are seldom
identical, this manual cannot possibly
provide detailed instructions and pre
cautions for each specific application.
Therefore, it is the owner/installer's re
sponsibility to ensure that applications
not addressed in this manual are per
formed only after establishing that nei
ther operator safety nor pump integrity
are compromised by the installation.
Before attempting to open or service the
pump:
1. Familiarize yourself with this man
ual.
2. Disconnect or lock out 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 volatile or flam
mable liquids which may damage the
pump or endanger personnel as a result
of pump failure.
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.
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.
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 cool before servicing.
Allow an over‐heated pump to com
pletely cool before servicing. Do not re

10 SERIESOM-06599
PAGE A - 2 SAFETY
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.
Do not operate the pump without
shields and/or guards in place over the
drive shafts, belts, and/or couplings, or
other rotating parts. Exposed rotating
parts can catch clothing, fingers, or
tools, causing severe injury to person
nel.
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-06599
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. Since the pressure supplied
to the pump is critical to performance and safety,
be sure to limit the incoming pressure to 50% of the
maximum permissible operating pressure as
shown on the pump performance curve (see Sec
tion E, Page 1).
For further assistance, contact your Gorman‐Rupp
distributor or the Gorman‐Rupp Company.
Pump Dimensions
See Figure B-1 for the approximate physical di
mensions of this pump.
OUTLINE DRAWING
Figure B-1. Pump Model 12B20-B /S1
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.

OM-06599 10 SERIES
PAGE B - 2 INSTALLATION
c. Carefully read all tags, decals, and markings
on the pump assembly, and perform all duties
indicated. Note that the pump shaft rotates in
the required direction.
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.
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
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.
The pump assembly can be seriously
damaged if the chains or cables used to lift
and move the unit are improperly wrapped
around the pump.
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
A minimum clearance of 18 inches in front of the
cover plate is required to permit removal of the cov
er and easy access to the pump interior.
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.

10 SERIES OM-06599
PAGE B - 3INSTALLATION
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 1‐1/4 inch
(31,8 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.
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 B-2
shows recommended minimum submergence vs.
velocity.

OM-06599 10 SERIES
PAGE B - 4 INSTALLATION
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
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.
A check valve in the discharge line is normally rec
ommended, but it is not necessary in low dis
charge head applications.
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

10 SERIES OM-06599
PAGE B - 5INSTALLATION
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.
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 cool be
fore servicing. Do not remove plates,
covers, gauges, or fittings from an over‐
heated pump. Liquid within the pump
can reach boiling temperatures, and va
por pressure within the pump can cause
parts being disengaged to be ejected
with great force. After the pump cools,
drain the liquid from the pump by re
moving the casing drain plug. Use cau
tion when removing the plug to prevent
injury to personnel 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.

OM-06599 10 SERIES
PAGE B - 6 INSTALLATION
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.
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.
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_.
The coupling is in alignment when the hub ends
are the same distance apart at all points (see Fig
ure B-3).
Figure B-3. Alignment of V‐Belt Driven
Pumps
Align non‐spider type couplings by using a feeler
gauge or taper gauge between the coupling halves
every 90_. The coupling is in alignment when the
hubs are the same distance apart at all points (see
Figure B-4).
Figure B-4. Alignment of V‐Belt Driven
Pumps
Check parallel adjustment by laying a straightedge
across both coupling rims at the top, bottom, and

10 SERIES OM-06599
PAGE B - 7INSTALLATION
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 B-5). 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 B-5. 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
guard in place over the rotating parts.
Exposed rotating parts can catch cloth
ing, fingers, or tools, causing severe in
jury to personnel.

OM-06599
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 volatile, or flam
mable liquids which may damage the
pump or endanger personnel 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 indicated
by an arrow on the pump body or accompanying
decals. If the pump is operated in the wrong direc
tion, the impeller could become loosened from the
shaft and seriously damage the pump.
The pump must operate in the direction in
dicated by the arrow on the pump, or ac
companying decals. Reverse rotation
could loosen the impeller and seriously
damage the pump.

OM-06599 10 SERIES
OPERATIONPAGE C - 2
Consult the operating manual furnished with the
pump 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
power source. Priming is indicated by a positive
reading on the discharge pressure gauge or by a
quieter operation. The pump may not prime imme
diately 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
160_F (71_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 cool before servicing 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 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).
Pump Vacuum Check
With the pump inoperative, install a vacuum gauge
in the system, using pipe dope on the threads.

OM-06599
10 SERIES
OPERATION PAGE C - 3
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, disconnect the power
source or lock it out to ensure that the pump will re
main inoperative.
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.
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.

TROUBLE POSSIBLE CAUSE PROBABLE REMEDY
PUMP FAILS TO
PRIME
Strainer clogged. Check strainer and clean if neces
sary.
Suction lift or discharge head too high. Check piping installation and install
bypass line if needed. See INSTAL
LATION.
Leaking or worn seal or pump gasket. Check pump vacuum. Replace
leaking or worn seal or gasket.
Lining of suction hose collapsed. Replace suction hose.
Air leak in suction line. Correct leak.
PUMP STOPS OR
FAILS TO DELIVER
RATED FLOW OR
PRESSURE
Air leak in suction line. Correct leak.
Lining of suction hose collapsed. Replace suction hose.
Not enough liquid in casing. Add liquid to casing. See
PRIMING.
Suction check valve contaminated or
damaged.
Clean or replace check valve.
Suction intake not submerged at
proper level or sump too small.
Check installation and correct
submergence as needed.
Impeller or other wearing parts worn
or damaged.
Replace worn or damaged parts.
Check that impeller is properly
centered and rotates freely.
OM-0659910 SERIES
TROUBLESHOOTING PAGE D - 1
TROUBLESHOOTING - SECTION D
Review all SAFETY information in Section A.
Before attempting to open or service the
pump:
1. Familiarize yourself with this manual.
2. Disconnect or lock out 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 open
ing any covers, plates, or plugs.
5. Close the suction and discharge
valves.
6. Vent the pump slowly and cautiously.
7. Drain the pump.

TROUBLE POSSIBLE CAUSE PROBABLE REMEDY
PUMP STOPS OR
FAILS TO DELIVER
RATED FLOW OR
PRESSURE (cont.)
PUMP REQUIRES
TOO MUCH
POWER
PUMP CLOGS
FREQUENTLY
Free impeller of debris.Impeller clogged.
Discharge head too low.
Dilute if possible.Liquid solution too thick.
Adjust discharge valve.
Open discharge valve fully to in
crease flow rate, and run power
source at maximum governed
speed.
Discharge flow too slow.
EXCESSIVE NOISE Cavitation in pump. Reduce suction lift and/or friction
losses in suction line. Record vac
uum and pressure gauge readings
and consult local representative or
factory.
Secure mounting hardware.Pump or drive not securely mounted.
Locate and eliminate source of air
bubble.
Pumping entrained air.
Suction check valve or foot valve
clogged or binding.
Clean valve.
Suction lift or discharge head too high. Check piping installation and install
bypass line if needed. See INSTAL
LATION.
Impeller clogged or damaged. Clean out debris; replace damaged
parts.
Leaking or worn seal or pump gasket. Check pump vacuum. Replace
leaking or worn seal or gasket.
Pump running backwards. Check direction of rotation and
correct by interchanging any two
motor leads at control box. (See
Pump Rotation, Section C).
Pump speed too slow. Check driver output; check belts
or couplings for slippage.
Pump speed too high. Check driver output check that
sheaves or couplings are correctly
sized.
BEARINGS RUN
TOO HOT
Bearing temperature is high, but
within limits.
Align drive properly.Drive misaligned.
Check piping installation for proper
support.
Suction and discharge lines not prop
erly supported.
Check for proper type and level of
lubricant.
Low or incorrect lubricant.
Check bearing temperature regular
ly to monitor any increase.
OM-06599 10 SERIES
TROUBLESHOOTINGPAGE D - 2

OM-0659910 SERIES
TROUBLESHOOTING PAGE D - 3
PREVENTIVE MAINTENANCE
Since pump applications are seldom identical, and
pump wear is directly affected by such things as
the abrasive qualities, pressure and temperature
of the liquid being pumped, this section is intended
only to provide general recommendations and
practices for preventive maintenance. Regardless
of the application however, following a routine pre
ventive maintenance schedule will help assure
trouble‐free performance and long life from your
Gorman‐Rupp pump. For specific questions con
cerning your application, contact your Gorman‐
Rupp distributor or the Gorman‐Rupp Company.
Record keeping is an essential component of a
good preventive maintenance program. Changes
in suction and discharge gauge readings (if so
equipped) between regularly scheduled inspec
tions can indicate problems that can be corrected
before system damage or catastrophic failure oc
curs. The appearance of wearing parts should also
be documented at each inspection for comparison
as well. Also, if records indicate that a certain part
(such as the seal) fails at approximately the same
duty cycle, the part can be checked and replaced
before failure occurs, reducing unscheduled down
time.
For new applications, a first inspection of wearing
parts at 250 hours will give insight into the wear rate
for your particular application. Subsequent inspec
tions should be performed at the intervals shown
on the chart below. Critical applications should be
inspected more frequently.
General Condition (Temperature, Unusual
Noises or Vibrations, Cracks, Leaks,
Loose Hardware, Etc.) I
Pump Performance (Gauges, Speed, Flow) I
Bearing Lubrication I R
Seal Lubrication (And Packing Adjustment,
If So Equipped) I R
V‐Belts (If So Equipped) I
Air Release Valve Plunger Rod (If So Equipped) I C
Front Impeller Clearance (Wear Plate) I
Rear Impeller Clearance (Seal Plate) I
Check Valve I
Pressure Relief Valve (If So Equipped) C
Pump and Driver Alignment I
Shaft Deflection I
Bearings I
Bearing Housing I
Piping I
Driver Lubrication - See Mfgr's Literature
Legend:
I = Inspect, Clean, Adjust, Repair or Replace as Necessary
C = Clean
R = Replace
* Service interval based on an intermittent duty cycle equal to approximately 4000 hours annually.
Adjust schedule as required for lower or higher duty cycles or extreme operating conditions.
Preventive Maintenance Schedule
Item Daily Weekly Monthly Semi‐
Annually
Annually
Service Interval*