GORMAN-RUPP PUMPS Roto-Prime RS Series Owner's manual

PUBLICATION NUMBER OM-03989
January 21, 1994
Rev. D 05‐10‐12
THE GORMAN‐RUPP COMPANY MANSFIELD, OHIO
GORMAN‐RUPP OF CANADA LIMITED ST. THOMAS, ONTARIO, CANADA Printed in U.S.A.
www.grpumps.com
1994 The Gorman‐Rupp Company
RS AND RD
SERIES PUMPS

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:

OM-03989 RS AND RD SERIES PUMPS
PAGE I - 1INTRODUCTION
INTRODUCTION
Thank You for purchasing a Gorman‐Rupp RS or
RD Roto‐Prime Series 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.
A set of three manuals accompanies your pump.
Each set consists of three parts; the Installation/
Operation Manual contains essential information
on installing and operating the pump. However,
since pump installations are seldom identical,
some of the information only summarizes general
recommendations and practices required to in
spect, position, and arrange the pump and piping.
The Parts List Manual provides performance
curve(s), a pump model cross‐section drawing,
and parts list for your pump.
The Maintenance and Repair Manual provides
troubleshooting and maintenance instructions re
quired to properly diagnose operational problems,
and to service the pump components. Contact the
factory for the authorized repair facility closest to
you.
This pump is a Roto‐Primeself‐priming centrifu
gal petroleum pump, designed to handle petro
leum products only. It incorporates an integral va
riable‐capacity vane pump which automatically
evacuates air and vapor from the suction line. This
pump should not be used to handle water or other
non‐petroleum liquids. For specific service, con
tact your Gorman‐Rupp distributor or the Gorman‐
Rupp Company.
The basic pump is not furnished with a mounting
base and power source; however, these items are
available from the factory as optional equipment.
The pump is designed to be driven by an explo
sion‐proof motor with a maximum full load speed
of either 1750 RPM (RS Series) or 3450 RPM (RD
Series).
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.
If there are any questions regarding the pump
which are not covered in this manual or in other lit
erature accompanying the 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]
CONTENTS
SAFETY - SECTION A
INSTALLATION - SECTION B
GENERAL INFORMATION PAGE B - 1.....................................................
PUMP DIMENSIONS PAGE B - 1..........................................................
PREINSTALLATION INSPECTION PAGE B - 1...............................................
POSITIONING PUMP PAGE B - 2..........................................................
GROUNDING PAGE B - 2................................................................
SUCTION AND DISCHARGE PIPING PAGE B - 2............................................
SUCTION LINES PAGE B - 3..............................................................
DISCHARGE LINES PAGE B - 6...........................................................
ALIGNMENT PAGE B - 7.................................................................

OM-03989RS AND RD SERIES PUMPS
PAGE I - 2 INTRODUCTION
OPERATION - SECTION C
GENERAL INFORMATION PAGE C - 1.....................................................
PRIMING PAGE C - 1....................................................................
STARTING PAGE C - 4...................................................................
OPERATION PAGE C - 4.................................................................
STOPPING PAGE C - 5...................................................................
BEARING TEMPERATURE CHECK PAGE C - 5.............................................
RECORDING MODEL AND
SERIAL NUMBERS
Please record the pump model, serial number, volt
age, and motor frame size in the spaces provided
below. Your Gorman‐Rupp distributor needs this
information when you require parts or service.
Pump Model:
Serial Number:
WARRANTY INFORMATION
The warranty provided with your pump is part of
Gorman‐Rupp's support program for customers
who operate and maintain their equipment as de
scribed in this and the other accompanying litera
ture. Please note that should the equipment be
abused or modified to change its performance be
yond the original factory specifications, the war
ranty will become void and any claim will be de
nied.
The following are used to alert personnel to procedures which require special attention, 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 de
scribe the requirements and the possible
damage which could result from failure to
follow the procedure.
NOTE
Instructions to aid in installation, operation, and
maintenance or which clarify a procedure.

OM-03989 RS AND RD SERIES PUMPS
PAGE A - 1SAFETY
SAFETY - SECTION A
The following information applies
throughout this manual to Gorman‐
Rupp RS and RD Roto‐PrimerSeries
basic pumps.
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 install, operate, or
service this pump, familiarize yourself
with this manual, and with all other liter
ature shipped with the pump. Unfamil
iarity with all aspects of pump operation
covered in this manual could lead to de
struction of equipment, injury, or death
to personnel.
Before attempting to open or service the
pump:
1. Familiarize yourself with this man
ual.
2. Shut off the incoming power to the
motor and lock it out, or take other
action 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 petro
leum products or other similar hydro
carbon liquids. Do not attempt to pump
water, corrosive materials, or any liq
uids which may damage the pump or en
danger personnel as a result of pump
failure.
This pump is designed to be used with
volatile and/or flammable liquids; be
certain proper safety practices are fol
lowed before operating or servicing the
pump. Provide adequate ventilation,
prohibit smoking, wear static‐resistant
clothing and shoes. Clean up all fuel
spills immediately after occurrence.
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.

RS AND RD SERIES PUMPS OM-03989
PAGE A-2 SAFETY
After the pump has been installed, make
certain that the pump and all piping con
nections are tight, properly supported
and secure before operation.
This pump is designed to be used with
volatile and/or flammable liquids; over
heating may produce dangerous fumes.
Take precautions to ensure the area sur
rounding the pump is adequately venti
lated. Allow the pump to completely
cool and use extreme caution when
venting the pump, or when removing
covers, plates, plugs, or fittings.
Overheated pumps can cause severe
burns and injuries, and produce explo
sive fumes. 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 install and operate a non‐explo
sion proof motor in an explosive atmo
sphere. Install, connect, and operate
the motor in accordance with The Na
tional Electric Code and all local codes.
If there is a conflict between the instruc
tions in the manual accompanying the
unit and The National Electric Code or
the applicable local code, The National
or local code shall take precedence. All
electrical equipment supplied with this
pump conformed to applicable federal
regulations and national codes in effect
on the date of manufacture.
This pump is not designed to handle water.
Operation of the pump with water or water‐
based solutions will damage the group
grind within the vane‐type priming pump.
Do not connect this pump to a storage
tank which has been filled with water until
the tank and lines have been completely
drained and flushed. Install a commercially
available 80 mesh screen and a filter in the
suction line to prevent debris from entering
the pump. Check pump rotation with the
suction line disconnected.

OM-03989 RS AND RD SERIES PUMPS
PAGE B - 1INSTALLATION
INSTALLATION - SECTION B
GENERAL INFORMATION
Review all SAFETY information in Section A.
Since pump installations are seldom identical, this
section is intended only to summarize general rec
ommendations and practices required to inspect,
position, and arrange the pump and piping. If there
are any questions concerning your specific instal
lation, contact your Gorman‐Rupp distributor or
the Gorman‐Rupp Company.
This pump is not designed to handle water.
Operation of the pump with water or water‐
based solutions will damage the group
grind within the vane‐type priming pump.
Do not connect this pump to a storage
tank which has been filled with water until
the tank and lines have been completely
drained and flushed. Install a commercially
available 80 mesh screen and a filter in the
suction line to prevent debris from entering
the pump. Check pump rotation with the
suction line disconnected.
Most of the information pertains to a standard stat
ic lift application, where the pump is positioned
above the free level of the 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 mount
ing, line configuration, and priming must be tai
lored to the specific application. Since the pres
sure supplied to the pump is critical to perform
ance and safety, be sure to limit the incoming pres
sure to 50% of the maximum permissible operating
pressure shown on the pump performance curve.
For further assistance, contact your Gorman‐Rupp
distributor or the Gorman‐Rupp Company.
PUMP DIMENSIONS
For the approximate physical dimensions of your
pump, refer to the pump specification data sheet or
contact your Gorman‐Rupp distributor or the Gor
man‐Rupp Company.
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. Note the direction of rotation indi
cated on the pump. Check that the pump
shaft rotates in the required direction.
Only operate this pump in the direction in
dicated on the pump body and/or the ac
companying decal. Reverse rotation of the
shaft will adversely effect pump perform
ance, and the pump could be seriously
damaged.
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 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.

RS AND RD SERIES PUMPS OM-03989
PAGE B - 2 INSTALLATION
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 5
times the weight of the pump, including the
weight of options and customer installed
accessories. Customer installed equipment such
as suction and discharge piping and fittings must
be removed before attempting to lift the pump.
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.
For the approximate weight of your pump, refer to
the pump specification data sheet or contact your
Gorman‐Rupp distributor or the Gorman‐Rupp
Company.
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.
When the pump is installed under unusual
conditions, the priming tube(s) may vi
brate abnormally. If this occurs after the
pump and piping are properly secured,
contact the factory to obtain optional
springs for the priming pump group grind.
If the vibration is not corrected, the tubing
could fatigue and rupture, spilling the liq
uid being pumped and resulting in a fire
hazard.
GROUNDING
To eliminate electrostatic build‐up by the liquid be
ing pumped, it is recommended that the pump be
grounded by attaching a ground wire assembly to
a ground rod. Install the ground rod in accordance
with the National Electrical Code and all local
codes. Be sure the clamp or fastener has made a
tight electrical connection with the rod.
Inspect and test the ground wire assembly
for conductivity. Replace broken or frayed
wire before resuming operation.
SUCTION AND DISCHARGE PIPING
Damage to the pump resulting from debris
in the suction line will not be covered by the
pump warranty. Before connecting the
suction and discharge piping, carefully
check the storage tank and piping for con
struction debris such as nuts, bolts, wire,
weld slag, and other foreign material. In
stall a commercially available 80 mesh
screen and a filter in the suction line to pre
vent debris from entering the pump.
Pump performance is adversely effected by in
creased suction lift, discharge elevation, and fric
tion losses. See the performance curve and oper
ating range shown in the Parts List manual to be
sure your overall application allows the pump to
operate within the safe operation range.

OM-03989 RS AND RD SERIES PUMPS
PAGE B - 3INSTALLATION
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.
Refer to Figure 1 for the recommended configura
tion of the suction line.
INCORRECT PITCH
VAPOR
POCKETS
INCORRECT LOOPS
RECOMMENDED
NO
POCKETS
PITCH UP TO
SUCTION
WITH NO
LOOPS
VAPOR
POCKETS
Figure 1. Suction Line Configuration

RS AND RD SERIES PUMPS OM-03989
PAGE B - 4 INSTALLATION
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.
Refer to Figure 2 for the recommended entrance
conditions using fittings.
POOR ENTRANCE CONDITIONS
RECOMMENDED ENTRANCE CONDITIONS
CHECK
VALVE
REDUCER HORIZONTAL
ELBOW
GATE
VALVE
3 TO 4 DIA'S OF
STRAIGHT PIPE
ECCENTRIC
REDUCER
3 TO 4 DIA'S OF
STRAIGHT PIPE GATE
VALVE
HORIZONTAL
ELBOW
Figure 2. Entrance Conditions Using Fittings
Strainers
A suction strainer was not furnished with this pump
since it is not designed to handle liquids containing
solids. However, to protect the pump from acciden
tal damage a commercially available 80 mesh
screen should be installed in the suction line. Make
certain that the total open area of the screen is at
least three or four times the cross section of the
suction line to ensure an adequate supply of liquid
to the pump.
Damage to the pump resulting from debris
in the suction line will not be covered by the
pump warranty. Before connecting the
suction and discharge piping, carefully
check the storage tank and piping for con
struction debris such as nuts, bolts, wire,
weld slag, and other foreign material. In
stall a commercially available 80 mesh
screen and a filter in the suction line to pre
vent debris from entering the pump.
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-03989 RS AND RD SERIES PUMPS
PAGE B - 5INSTALLATION
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 3 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 3. Recommended Minimum Suction Line Submergence vs. Velocity

RS AND RD SERIES PUMPS OM-03989
PAGE B - 6 INSTALLATION
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
Some pump models are provided with an integral
priming pump check valve in the discharge port.
This check valve is designed to prevent recircula
tion of air or vapor ejected during the priming cycle.
It will not serve as a discharge check valve in the
system piping. If the application involves static dis
charge head or suction pressures, a check valve
must be installed to prevent siphoning or loss of
prime through the bypass line. If a system check
valve is required, it must be installed in addition to
the built‐in priming pump check valve.
Priming Lines
The integral Roto‐Primepriming pump incorpo
rates a priming line which evacuates the suction
line effectively against back pressure ranging from
atmospheric pressure up to approximately 8 psi
(measured downstream of the discharge check
valve). If static discharge pressure exceeds 8 psi,
an Air Release Valve must be installed to permit the
escape of air or vapor to atmosphere during initial
priming or repriming cycle. This valve functions in
conjunction with three priming tubes installed be
tween the Air Release Valve, the priming pump and
the pump suction.
Air Release Valves (“BAR” Models)
Some pump models are provided with an Air Re
lease Valve. If the pump does not have an Air Re
lease Valve, it can be ordered as optional equip
ment. Since internal changes are required on the
pump to facilitate installation and proper function
of the Air Release Valve, it is recommended that
this be ordered as a factory installed option only.
The Air Release Valve works in conjunction with the
integral priming pump to expel and prevent recir
culation of air or vapor ejected during the priming
cycle. The Air Release Valve will not serve as a
throttling valve or check valve in the system piping.
If the application involves static discharge head or
suction pressure, system check valve must be in
stalled to prevent siphoning or loss of prime
through the pump.
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.
Air Release Valve Venting (“BAR” Models)
When ordered as a factory installed option, the Air
Release Valve is shipped mounted on the pump
base with the valve tubing connected. If the Air Re
lease Valve is shipped separately, refer to the in
stallation instructions accompanying the Valve.
Remove the shipping plug in the head of the Air Re
lease Valve so that normal operation and venting
can take place. It is suggested that a length of 3/4
inch tubing be installed in the shipping plug open
ing so that hazardous vapors can be carried away
from the immediate vicinity of the pump.
NOTE
When two pumps equipped with Air Release Valves
are installed in parallel, a check valve must be in
stalled in the venting lines.

OM-03989 RS AND RD SERIES PUMPS
PAGE B - 7INSTALLATION
If the pump is installed within a closed
building such as a pump house, venting
lines to the outside of the building should
be installed in accordance with National
and local codes.
Bypass Lines (“BAR” Models)
The integral Roto‐Primepriming pump and Air
Release Valve work in conjunction with three tube
assemblies. One tube assembly draws vapor from
the suction flange of the centrifugal pump to the
suction port of the priming pump. Another assem
bly discharges the vapor to the air release. The
third tube assembly returns any accumulated liq
uid from the bottom of the cylindrical air release
chamber back into the suction flange of the cen
trifugal pump.
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 4).
Figure 4. Aligning 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 5).
Check parallel adjustment by laying a straightedge
across both coupling rims at the top, bottom, and

RS AND RD SERIES PUMPS OM-03989
PAGE B - 8 INSTALLATION
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.
Figure 5. Aligning Non‐Spider Type Couplings
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-03989 RS AND RD SERIES PUMPS
PAGE C - 1OPERATION
OPERATION - SECTION C
GENERAL INFORMATION
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 petro
leum products or other similar hydro
carbon liquids. Do not attempt to pump
water, corrosive materials, or any liq
uids which may damage the pump or en
danger personnel as a result of pump
failure.
This pump is not designed to handle water.
Operation of the pump with water or water‐
based solutions will damage the group
grind within the vane‐type priming pump.
Do not connect this pump to a storage
tank which has been filled with water until
the tank and lines have been completely
drained and flushed. Install a commercially
available 80 mesh screen and a filter in the
suction line to prevent debris from entering
the pump. Check pump rotation with the
suction line disconnected.
Pump speed and operating condition
points must be within the continuous per
formance range shown on the curve (see
the Parts List Manual, 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).
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.
If the pump is installed within a closed
building such as a pump house, venting
lines to the outside of the building should
be installed in accordance with National
and local codes.
Priming Pump
Before starting the pump for the first time, carefully
remove the spring cap, gasket and pressure regu
lating spring located in the top of the group grind
(see the parts list for identification). Pour approxi
mately 4 ounces (0,12 liter) of SAE 10 or 20 non‐de
tergent oil into the group grind to lubricate the shaft
seal and group grind rotor blades. Reinstall the
spring, gasket and cap.
Before attempting to start the motor, rotate the
pump shaft by hand to ensure the oil is evenly dis
tributed within the group grind. If the shaft does not
rotate by hand, allow the pump to sit to absorb the
lubricating oil and then rotate the shaft again. Do
not start the pump motor until the shaft has been
rotated by hand.
Whenever air or vapor is present in the suction line,
whether at start‐up or during pumping operation,

RS AND RD SERIES PUMPS OM-03989
PAGE C - 2 OPERATION
the spring located on top of the rotor forces the
group grind into its maximum eccentric position to
automatically evacuate the air vapor through the
priming tube and into the pump discharge.
When the pump is installed under unusual
conditions, the priming tube(s) may vi
brate abnormally. If this occurs after the
pump and piping are properly secured,
contact the factory to obtain optional
springs for the priming pump group grind.
If vibration is not corrected, the tubing
could fatigue and spill the liquid being
pumped, resulting in a fire hazard.
As air and vapor is evacuated and the main cen
trifugal pump begins to deliver liquid, the resulting
priming pump discharge pressure builds up
against the underside of the slide and moves it to
ward the neutral (centered) position. After all the air
and vapor is removed and the centrifugal pump
reaches full capacity, the priming pump discharge
pressure overcomes the spring pressure on the
slide and moves it towards the neutral position
where it remains until air or vapor enters the sys
tem. While in the neutral position, the priming
pump operates at minimum capacity and circu
lates only a small amount of liquid. See Figure 2 for
the theory of priming pump operation.
FULL PRIMING
(SPRING FULLY EXTENDED,
SLIDE AT BOTTOM, MAXI
MUM VAPOR EVACUATION)
PARTIAL PRIMING
(SPRING SLIGHTLY COMPRESSED,
SLIDE MOVING TOWARD CENTER,
VAPOR MOSTLY EVACUATED)
NEUTRAL
(SPRING FULLY COM
PRESSED, SLIDE CENTERED,
VAPOR FULLY EVACUATED)
Figure 2. Automatic Priming Sequence
Priming is rapid, but not instantaneous. The prim
ing pump will prime an absolutely dry line of four
inch diameter in approximately two seconds per
foot of suction pipe. Thus, if the suction line is 10
feet long, the pump will prime in approximately 20
seconds. If the pump continually handles dry liq
uids, such as gasoline or solvents, priming pump
vane wear may result, causing a loss of priming
vacuum. If priming time increases significantly
over a period of time, check the priming pump
vanes for excessive wear.
NOTE
A special seal is available for pumps which are to
handle solvents. When ordering a pump or replace
ment parts, specify what solvent the pump is to han
dle.
Priming Pump Group Grind Check
With the pump inoperative, remove the group
grind drain plug and drain any liquid from the
group grind. Remove the spring cap and pressure
regulating spring. Insert a screwdriver or other suit
able tool into the drain plug hole, and move the
slide up and down. The slide should travel 1/8 inch
(3,2 mm) from the full priming position to the neu

OM-03989 RS AND RD SERIES PUMPS
PAGE C - 3OPERATION
tral position. If it does not, flush the group grind
with penetrating oil, and check the slide travel
again. The slide should move freely. Reinstall the
pressure regulating spring and spring cap, and
clean and reinstall the drain plug.
Air Release Valve (“BAR” Models)
When properly installed, the Air Release Valve al
lows the integral Roto‐Primepriming pump to
overcome relatively high static discharge heads or
back pressure during the priming cycle. Figure 1
shows a schematic configuration of the valve and
is keyed to the following description of operation.
DISCHARGE LINE CHECK
VALVE (MANDATORY)
VENT TO OUTSIDE IF INSTALLED IN
PUMP HOUSE (CHECK VALVE REQUIRED
ON DUPLEX INSTALLATION ONLY)
DISCHARGE
SUCTION
AIR RELEASE
VALVE
GORMAN‐RUPP ROTO‐PRIME
SELF‐PRIMING CENTRIFUGAL PUMP
A
B
C
D
E
Figure 1. Gorman-Rupp Air Release Valve Connected To Roto-PrimePump
The Air Release Valve is designed with an air valve
in the head of the assembly and a sump valve in the
base of the assembly. These valves are controlled
by a common rod which is moved vertically by an
attached float.
When the pump is first installed, there is air in the
suction line, the Air Release Valve is open, and
there is back pressure against the discharge line
check valve “D”.
When the pump is started, air is drawn from the
suction line into the priming pump through the
priming tube “A”, compressed by the priming
pump, and discharged through the discharge tube
“B” to the Air Release Valve. This air and vapor is
then vented to the atmosphere through the valve
head.
With the float down, sump valve “E” is closed; air
cannot re‐enter the suction piping through the re
turn tube assembly “C”.
As product fills the pump casing, the impeller de
velops pressure, opening check valve “D” in the
discharge piping. The priming pump will deliver
product, filling the float chamber. The float will rise,
opening sump valve “E”, and closing the air valve.

RS AND RD SERIES PUMPS OM-03989
PAGE C - 4 OPERATION
The product recirculates through the return tube
assembly “C” to the pump suction flange. The liq
uid pressure equalizes the priming pump spring
pressure and the priming pump slides into neutral.
At this point the pump is fully primed.
In neutral position the priming pump circulates a
small amount of liquid through the discharge tube
to the float chamber through the return tube and
back into the suction flange.
If air or vapor enters the suction piping during the
pumping operation, again the discharge line
check valve will close, and the priming pump will
again evacuate the air through the Air Release
Valve.
STARTING
Consult the operations manual furnished with the
power source.
Before connecting a motor to the incoming power,
check that the electrical service available matches
the pump motor requirements stamped on the mo
tor nameplate. Check that the motor speed meets
pump specifications. The pump is designed to be
driven at a maximum full load speed of either 1750
RPM (RS Series) or 3450 RPM (RD Series).
Rotation
The correct direction of pump rotation is indicated
by an arrow on the pump body or accompanying
decals. The pump could be damaged and per
formance adversely affected by incorrect rotation.
If pump performance is not within the specified lim
its (see the curve in the Parts List Manual on page
1), check the direction of rotation before further
troubleshooting.
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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.
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 cools, drain the liquid from
the pump by removing the casing drain
plug. Use caution when removing the
plug to prevent injury to personnel from
hot liquid.

OM-03989 RS AND RD SERIES PUMPS
PAGE C - 5OPERATION
Strainer Check
A suction strainer was not furnished with this pump
but an 80 mesh screen may have been installed by
the user. Check the screen regularly, and clean it
as necessary. The screen should also be checked
if pump flow rate begins to drop. If a vacuum suc
tion gauge has been installed, monitor and record
the readings regularly to detect screen blockage.
Pump Vacuum Check
NOTE
Petroleum products are very sensitive to changes
in temperature. Warmer temperatures elevate the
product vapor pressure resulting in low vacuum
readings. Do not mistake temperature problems for
faulty pump installation or performance.
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 15
to 17 inches (381 to 432 mm) or more of mercury
for petroleum. If it does not, check for air leaks in
the seal, gasket, or discharge 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, shut off the incoming
power and lock it out, or take other action to ensure
that the pump will remain inoperative.
Cold Weather Preservation
Since the application of this pump is limited to pe
troleum products, normal freezing conditions will
not damage the pump. However, during extremely
severe conditions care should be exercised during
start‐up, especially if the pump has been idle for
more than a few hours.
BEARING TEMPERATURE CHECK
The standard bearings used in this pump are per
manently sealed and lubricated by the manufac
turer. However due to temperature changes and
the danger of moisture contamination, the bearing
cavity is also partially filled with grease.
Optional oil lubricated bearings are not fully
sealed, and oil is required within the bearing hous
ing to lubricate them and protect them from mois
ture condensation.
Monitor the condition of the bearing lubri
cant regularly for evidence of rust or mois
ture condensation. This is especially im
portant in areas where variable hot and
cold temperatures are common.
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).

RS AND RD SERIES PUMPS OM-03989
PAGE C - 6 OPERATION
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.