GORMAN-RUPP PUMPS VG Series Application guide

OM-02819-02
September 11, 2000
Rev. B 09‐25‐12
ACE
THE GORMAN‐RUPP COMPANY MANSFIELD, OHIO
www.grpumps.com
GORMAN‐RUPP OF CANADA LIMITED ST. THOMAS, ONTARIO, CANADA Printed in U.S.A.
2000 The Gorman‐Rupp Company
INSTALLATION, OPERATION,
AND MAINTENANCE MANUAL
WITH PARTS LIST
VG SERIES PUMP
MODEL
VG8D3-B

Register your new
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.................................................
WARNINGS - 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.............................................................
SUCTION AND DISCHARGE PIPING PAGE B - 2.........................................
Materials PAGE B - 2..............................................................
Line Configuration PAGE B - 2......................................................
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 - 3.................................................
Suction Line Positioning PAGE B - 4................................................
DISCHARGE LINES PAGE B - 4........................................................
Siphoning PAGE B - 4.............................................................
Valves PAGE B - 4................................................................
ALIGNMENT PAGE B - 5..............................................................
Coupled Drives PAGE B - 5........................................................
V-Belt Drives PAGE B - 5.........................................................
OPERATION - SECTION C PAGE C - 1......................................
PRIMING PAGE C - 1.................................................................
Hand Primers Page C - 1..........................................................
Exhaust Primers Page C - 1.......................................................
Auxiliary Ejectors Page C - 2.......................................................
Vacuum Pumps Page C - 2........................................................
STARTING PAGE C - 2................................................................
Rotation Page C - 2..............................................................
OPERATION PAGE C - 2..............................................................
Leakage PAGE C - 2..............................................................
Liquid Temperature And Overheating PAGE C - 2.....................................
Strainer Check PAGE C - 3.........................................................
Pump Vacuum Check PAGE C - 3..................................................
STOPPING PAGE C - 3................................................................
Cold Weather Preservation PAGE C - 3..............................................
BEARING TEMPERATURE CHECK PAGE C - 4..........................................
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........................................
PUMP MODEL - PARTS LIST PAGE E - 3...............................................
PUMP AND SEAL DISASSEMBLY AND REASSEMBLY PAGE E - 4.........................
Impeller Removal PAGE E - 4......................................................
Seal Removal PAGE E - 4..........................................................
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 PAGE E - 8.....................................................
Final Pump Assembly PAGE E - 8..................................................
LUBRICATION PAGE E - 8.............................................................
Seal Assembly PAGE E - 8.........................................................
Bearings PAGE E - 8..............................................................
Power Source PAGE E - 9.........................................................

VG SERIES OM-02819
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 VG Series, enclosed impeller, cen
trifugal model with straight‐in suction without a
suction check valve. The pump is designed for
high pressure distribution of liquids containing
specified entrained solids. The basic material of
construction for wetted parts is gray iron. Be sure
the liquid being pumped is compatible with this
material.
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.
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]
For information or technical assistance on the
power source, contact the power source manufac
turer's local dealer or representative.
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.

VG SERIES OM-02819
PAGE A - 1SAFETY
SAFETY - SECTION A
This information applies to VG Series
basic pumps. Gorman‐Rupp has no
control over or particular knowledge of
the power source which will be used.
Refer to the manual accompanying the
power source before attempting to be
gin operation.
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 liquids
containing specified entrained solids.
Do not attempt to pump volatile, corro
sive, or flammable materials which may
damage the pump or endanger person
nel as a result of pump failure.
After the pump has been positioned,
make certain that the pump and all pip
ing connections are tight, properly sup
ported and secure before operation.
Do not operate the pump without the
guards in place over the rotating parts.
Exposed rotating parts can catch cloth
ing, fingers, or tools, causing severe in
jury to personnel.
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.
Use lifting and moving equipment in
good repair and with adequate capacity
to prevent injuries to personnel or dam
age to equipment. Suction and dis
charge hoses and piping must be re
moved from the pump before lifting.
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.

OM-02819VG SERIES
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 posi
tioned 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.
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 1. Pump Model VG8D3-B

OM-02819 VG 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 warnings and cautions con
tained in this manual or affixed to the pump,
and perform all duties indicated. Note the di
rection of rotation indicated on the pump.
Check that the pump shaft rotates counter
clockwise when facing the pump suction.
Only operate this pump in the direction in
dicated by the arrow on the pump body
and on the accompanying decal. Refer to
ROTATION in OPERATION, Section C.
d. Check all lubricant levels and lubricate as
necessary. Refer to LUBRICATION in the
MAINTENANCE AND REPAIR section of this
manual and perform duties as instructed.
e. If the pump and power source have been
stored for more than 12 months, some of the
components or lubricants may have ex
ceeded their maximum shelf life. These must
be inspected or replaced to ensure maxi
mum 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
Use lifting equipment with a capacity of at least
3,510 pounds (1592,1 kg). This pump weighs ap
proximately 702 pounds (318,4 kg), not including
the weight of accessories and base. Customer in
stalled equipment such as suction and discharge
piping must be removed before attempting to lift.
The pump assembly can be seriously
damaged if the cables or chains 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.
SUCTION AND DISCHARGE PIPING
The size of the system piping is not always deter
mined by the nominal suction and discharge port
diameter. Factors such as suction lift, discharge
elevation, and friction losses for the complete sys
tem must be considered to be sure your applica
tion allows the pump to operate within the safe op
erating range shown on page E‐1. In any case, the
suction line should never be smaller than the pump
inlet.
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

OM-02819VG SERIES
PAGE B - 3INSTALLATION
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 1/16 inch
(26,9 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

OM-02819 VG SERIES
PAGE B - 4 INSTALLATION
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 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
A check valve in the discharge line is normally rec
ommended, but it is not necessary in low dis
charge head applications.
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.

OM-02819VG SERIES
PAGE B - 5INSTALLATION
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 de
grees. The coupling is in alignment when the hub
ends are the same distance apart at all points (see
Figure 3A).
Figure 3A. Aligning Spider‐Type Couplings
Figure 3B. 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 3B).
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 3C). In drive
systems using two or more belts, make certain that
the belts are a matched set; unmatched sets will
cause accelerated belt wear.

OM-02819 VG SERIES
PAGE B - 6 INSTALLATION
MISALIGNED:
SHAFTS
NOT PARALLEL
MISALIGNED:
SHAFTS
NOT IN LINE
ALIGNED: SHAFTS
PARALLEL AND
SHEAVES IN LINE
Figure 3C. 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.

VG SERIES OM-02819
OPERATION PAGE C - 1
OPERATION - SECTION C
Review all SAFETY information in Section A.
Follow the instructions on all tags, labels and de
cals attached to the pump.
This pump is designed to handle liquids
containing specified entrained solids.
Do not attempt to pump volatile, corro
sive, or flammable liquids which may
damage the pump or endanger person
nel as a result of pump failure.
Pump speed and operating conditions
must be within the performance range
shown on page E‐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 is not a self‐priming pump, so an external
priming device must be used if the pump is in
stalled on a suction lift. A foot valve may be in
stalled at the end of the suction pipe to maintain the
prime; however, this may adversely affect pump
performance due to friction loss. Many standard
centrifugal models are equipped with a hand‐oper
ated vacuum pump, exhaust primer, or ejector for
this purpose. If a priming device was not furnished
with the pump, it may be ordered from the factory
as an option. Before attempting to operate the
priming device, close the discharge throttling
valve. (Installation of a spring‐loaded check valve
is also recommended to facilitate priming.) Once
the pump is fully primed, close the valve between
the priming device and pump to preserve the
prime. Start the pump and open the discharge
valve slowly to fill the discharge line. When installed
in a flooded suction application, simply open the
system valves and permit the incoming liquid to
evacuate the air. After the pump and piping system
have completely filled, evacuate any remaining air
pockets in the pump or suction line.
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.
Hand Primers
Hand‐operated primers are usually mounted on
the pump and, when operated, draw air out of the
suction line and pump casing. To prime a pump
with a hand vacuum pump, open the cock on the
pump priming line. Operate the hand pump until
liquid flows out of the check valve on the bottom of
the primer pump. Once the pump is primed, close
the valve located between the primer and the
pump so that the prime will not be lost.
DRAIN
COCK
HANDLE
Figure 1. Hand Primer Assembly
Exhaust Primers
Engine driven pumps normally take advantage of
the engine exhaust gases by using them to operate
an exhaust primer. The exhaust is directed through

VG SERIESOM-02819
OPERATIONPAGE C - 2
a venturi which creates a vacuum in the pump cas
ing in order to fill the suction line and pump casing
with liquid. To prime a pump using an exhaust
primer, open the gas cock in the priming line and
engage the exhaust primer until liquid is thrown out
of the ejector nozzle.
GAS
COCK
HANDLE
Figure 2. Exhaust Primer Assembly
Air can be exhausted to prime a pump by using a
vacuum pump. Either a wet type or a dry type vac
uum pump may be used; however, a wet type is
preferred since it will not be damaged if liquid en
ters it. If a dry vacuum pump is used, provisions
must be made to keep liquid from entering it.
Auxiliary Ejectors
Ejectors function much like exhaust primers. They
may be operated by steam, compressed air, water
or exhaust gases. To prime a pump using an ejec
tor, open the gas cock in the priming line and oper
ate the ejector until liquid is thrown out the ejector
nozzle.
Vacuum Pumps
Air can be exhausted to prime a pump by using a
vacuum pump. Either a wet type or a dry type vac
uum pump may be used; however, a wet type is
preferred since it will not be damaged if liquid en
ters it. If a dry vacuum pump is used, provisions
must be made to keep liquid from entering it.
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, pump perform
ance could be adversely affected, and the pump
could be seriously damaged.
Only operate this pump in the direction in
dicated by the arrow on the pump body
and on the accompanying decal. Other
wise, pump performance could be ad
versely affected, and the pump could be
seriously damaged.
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
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 (71,1C). Do not apply it at a higher operat
ing temperature.
Overheating can occur if operated with the valves
in the suction or discharge lines closed. Operating

VG SERIES OM-02819
OPERATION PAGE C - 3
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.
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.
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.
Pump Vacuum Check
Since this pump does not have a suction check
valve, the discharge line must be fitted with a check
valve if a pump vacuum reading is to be taken.
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.
On engine driven pumps, reduce the throttle
speed slowly and allow the engine to idle briefly be
fore stopping.
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 to ensure that the pump will remain inop
erative.
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.

VG SERIESOM-02819
OPERATIONPAGE C - 4
BEARING TEMPERATURE CHECK
Bearings normally run at higher than ambient tem
peratures because of heat generated by friction.
Temperatures up to 160F (71,1C) are consid
ered normal for bearings, and they can operate
safely to at least 180F (82,2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 temperature 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 MAINTENANCE
AND REPAIR). Bearing overheating can also be
caused by shaft misalignment and/or excessive vi
bration.
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.

VG‐SERIES OM-02819
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. 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 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 FAILS TO
PRIME
Air leak in suction line.
Lining of suction hose collapsed.
Correct leak.
Replace suction hose.
Leaking or worn seal or pump gasket. Check pump vacuum. Replace
leaking or worn seal or gasket.
Strainer clogged. Check strainer and clean if neces
sary.
PUMP STOPS OR
FAILS TO DELIVER
RATED FLOW OR
PRESSURE
Air leak in suction line. Correct leak.
Strainer clogged. Check strainer and clean if neces
sary.
Suction intake not submerged at
proper level or sump too small.
Check installation and correct sub
mergence as needed.
Auxiliary priming device faulty or im
properly installed.
Repair priming device or check in
stallation.
Discharge check valve open. Check position of handle; close
valve.
Pump running backwards. Check direction of rotation.
Impeller or other wearing parts worn
or damaged.
Replace worn or damaged parts.
Check that impeller is properly
centered and rotates freely.
Impeller clogged. Free impeller of debris.

VG‐SERIESOM-02819
TROUBLESHOOTINGPAGE D - 2
TROUBLE POSSIBLE CAUSE PROBABLE REMEDY
PUMP STOPS OR
FAILS TO DELIVER
RATED FLOW OR
PRESSURE (cont.)
PUMP REQUIRES
TOO MUCH
POWER
PUMP CLOGS
FREQUENTLY
Pump speed too slow. Check driver output; check belts
or couplings for slippage.
Suction lift too high. Measure lift w/vacuum gauge. Re
duce lift and/or friction losses in
suction line.
Pump speed too high. Check driver output; check that
sheaves or couplings are cor
rectly sized.
Discharge head too low. Adjust discharge valve.
Liquid solution too thick. Dilute if possible.
Bearing(s) frozen. Disassemble pump and check
bearing(s).
Discharge flow too slow. Open discharge valve fully to in
crease flow rate, and run power
source at maximum governed
speed.
Suction check valve or foot valve
clogged or binding.
Clean valve.
EXCESSIVE NOISE Cavitation in pump.
Impeller clogged or damaged.
Pump or drive not securely mounted.
Pumping entrained air.
Reduce suction lift and/or friction
losses in suction line. Record vac
uum and pressure gauge readings
and consult local representative or
factory.
Locate and eliminate source of air
bubble.
Secure mounting hardware.
Clean out debris; replace dam
aged parts.
Leaking or worn seal or pump gasket. Check pump vacuum. Replace
leaking or worn seal or gasket.
Discharge throttling valve partially
closed; check that valve is installed im
properly.
Open discharge valve fully; check
piping installation.
Liquid solution too thick. Dilute if possible.
Power source too small. Check power requirement for ap
plication. Install larger power
source.
Impeller jammed due to debris or in
sufficient clearance.
Disassemble pump and check im
peller.
Suction and discharge lines not prop
erly supported.
Check piping installation for proper
support.

VG‐SERIES OM-02819
TROUBLESHOOTING PAGE D - 3
TROUBLE POSSIBLE CAUSE PROBABLE REMEDY
BEARINGS RUN
TOO HOT
Bearing temperature is high, but
within limits.
Check bearing temperature regu
larly to monitor any increase.
Low or incorrect lubricant. Check for proper type and level of
lubricant.
Pump speed too high. Reduce speed of power source.
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.

VG‐SERIESOM-02819
TROUBLESHOOTINGPAGE D - 4
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*