GORMAN-RUPP PAH SERIES Application guide

OM-06449-01
March 29, 2012
Rev. C 09‐14‐16
GORMAN‐RUPP PUMPS
www.grpumps.com
2012 Gorman‐Rupp Pumps Printed in U.S.A.
INSTALLATION, OPERATION,
AND MAINTENANCE MANUAL
WITH PARTS LIST
PAH SERIESPUMP
MODEL
PAH6A60C-B

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TABLE OF CONTENTS
i
INTRODUCTION PAGE I - 1.................................................
SAFETY ‐ SECTION A PAGE A - 1............................................
INSTALLATION - SECTION B PAGE B - 1....................................
PREINSTALLATION INSPECTION PAGE B - 1............................................
POSITIONING PUMP PAGE B - 1.......................................................
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 - 2..................................................
Gauges PAGE B - 2...............................................................
SUCTION LINES PAGE B - 2...........................................................
Fittings PAGE B - 2...............................................................
Strainers PAGE B - 2..............................................................
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................................................................
ALIGNMENT PAGE B - 4..............................................................
Coupled Drives PAGE B - 4........................................................
Drive Belts PAGE B - 5............................................................
DRIVE BELT TENSIONING PAGE B - 5..................................................
General Rules of Tensioning PAGE B - 5.............................................
OPERATION - SECTION C PAGE C - 1......................................
PRIMING PAGE C - 1.................................................................
STARTING PAGE C - 1................................................................
Rotation PAGE C - 1..............................................................
OPERATION PAGE C - 1..............................................................
Leakage PAGE C - 1..............................................................
Liquid Temperature And Overheating PAGE C - 1.....................................
Strainer Check PAGE C - 2.........................................................
Pump Vacuum Check PAGE C - 2..................................................
STOPPING PAGE C - 3................................................................
BEARING TEMPERATURE CHECK PAGE C - 3..........................................
Cold Weather Preservation PAGE C - 3..............................................
TROUBLESHOOTING - SECTION D PAGE D - 1..............................
PREVENTIVE MAINTENANCE PAGE D - 3...............................................
PUMP MAINTENANCE AND REPAIR ‐ SECTION E PAGE E - 1.................
STANDARD PERFORMANCE CURVE PAGE E - 1........................................

TABLE OF CONTENTS
(continued)
ii
PARTS LISTS:
Pump Model PAGE E - 3..........................................................
Pump End Assembly PAGE E - 5...................................................
Priming Chamber Kit PAGE E - 6...................................................
Priming Chamber Assembly PAGE E - 7.............................................
PUMP AND SEAL DISASSEMBLY AND REASSEMBLY PAGE E - 8.........................
Priming Chamber Removal And Disassembly PAGE E - 8..............................
Discharge Check Valve Removal and Disassembly PAGE E - 9.........................
Suction Spool Removal PAGE E - 9.................................................
Pump Casing and Wear Ring Removal PAGE E - 9....................................
Impeller Removal PAGE E - 9......................................................
Seal Removal PAGE E - 10..........................................................
Pump Shaft and Bearing Removal and Disassembly PAGE E - 10........................
Bearing Cleaning And Inspection PAGE E - 11........................................
Pump Shaft and Bearing Reassembly and Installation PAGE E - 11......................
Seal Reassembly and Installation PAGE E - 13........................................
Impeller Installation PAGE E - 14.....................................................
Pump Casing and Wear Ring Installation PAGE E - 15..................................
Discharge Check Valve Assembly and Installation PAGE E - 16..........................
Priming Chamber Assembly And Installation PAGE E - 16...............................
LUBRICATION PAGE E - 16.............................................................
Seal Assembly PAGE E - 16.........................................................
Bearings PAGE E - 16..............................................................
Power Source PAGE E - 17.........................................................

PAH SERIES OM-06449
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.
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 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.
HAZARD AND INSTRUCTION
DEFINITIONS
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.

PAH SERIES OM-06449
PAGE A - 1SAFETY
SAFETY ‐ SECTION A
This information applies to Prime Aire
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.
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 and make
sure the pump is cool before open
ing 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, corro
sive, or flammable liquids which may
damage the pump or endanger person
nel as a result of pump failure.
Death or serious personal injury and
damage to the pump or components
can occur if proper lifting procedures
are not observed. Make certain that
hoists, chains, slings or cables are in
good working condition and of suffi
cient capacity and that they are posi
tioned so that loads will be balanced
and the pump or components will not be
damaged when lifting. Suction and dis
charge hoses and piping must be re
moved from the pump before lifting. Lift
the pump or component only as high as
necessary and keep personnel away
from suspended objects.
After the pump has been installed, make
certain that the pump and all piping or
hose connections are tight, properly
supported and secure before operation.
Do not operate the pump against a
closed discharge valve. If operated
against a closed discharge valve, pump
components will deteriorate, and the
liquid could come to a boil, build pres
sure, and cause the pump casing to rup
ture or explode. Momentary closure of a
discharge valve is acceptable only

PAH SERIESOM-06449
PAGE A - 2 SAFETY
when required for startup or shutdown
procedures.
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 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 completely before
servicing.
This pump may be used to handle mate
rials which could cause illness through
direct exposure or emitted fumes. Wear
adequate protective clothing when
working on the pump or piping.
Pumps and related equipment must be in
stalled and operated according to all na
tional, local and industry standards.

OM-06449PAH 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.
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 impeller.
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 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.
If the maximum shelf life has been exceeded, or if
anything appears to be abnormal, contact your
Gorman‐Rupp distributor or the factory to deter
mine the repair or updating policy. Do not put the
pump into service until appropriate action has
been taken.
POSITIONING PUMP
Death or serious personal injury and
damage to the pump or components
can occur if proper lifting procedures
are not observed. Make certain that
hoists, chains, slings or cables are in
good working condition and of suffi
cient capacity and that they are posi
tioned so that loads will be balanced
and the pump or components will not be
damaged when lifting. Suction and dis
charge hoses and piping must be re
moved from the pump before lifting. Lift
the pump or component only as high as

OM-06449 PAH SERIES
PAGE B - 2 INSTALLATION
necessary and keep personnel away
from suspended objects.
Lifting
Pump unit weights will vary depending on the
mounting and drive provided. Check the shipping
tag on the unit packaging for the actual weight, and
use lifting equipment with appropriate capacity.
Drain the pump and remove all customer‐installed
equipment such as suction and discharge hoses
or piping before attempting to lift existing, installed
units.
Mounting
Locate the pump in an accessible place as close as
practical to the liquid being pumped. Level mount
ing is essential for proper operation.
The pump may have to be supported or shimmed
to provide for level operation or to eliminate vibra
tion.
SUCTION AND DISCHARGE PIPING
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 on Page E‐1 to be sure your
overall application allows pump to operate within
the safe operation range.
Materials
Either pipe or hose maybe used for suction and
discharge lines; however, the materials must be
compatible with the liquid being pumped. If hose is
used in suction lines, it must be the rigid‐wall, rein
forced type to prevent collapse under suction. Us
ing piping couplings in suction lines is not recom
mended.
Line Configuration
Keep suction and discharge lines as straight as
possible to minimize friction losses. Make mini
mum use of elbows and fittings, which substan
tially increase friction loss. If elbows are necessary,
use the long‐radius type to minimize friction loss.
Connections to Pump
Before tightening a connecting flange, align it ex
actly with the pump port. Never pull a pipe line into
place by tightening the flange bolts and/or cou
plings.
Lines near the pump must be independently sup
ported to avoid strain on the pump which could
cause excessive vibration, decreased bearing life,
and increased shaft and seal wear. If hose‐type
lines are used, they should have adequate support
to secure them when filled with liquid and under
pressure.
Gauges
Most pumps are drilled and tapped for installing
discharge pressure and vacuum suction gauges. If
these gauges are desired for pumps that are not
tapped, drill and tap the suction and discharge
lines not less than 18 inches (457,2 mm) from the
suction and discharge ports and install the lines.
Installation closer to the pump may result in erratic
readings.
SUCTION LINES
To avoid air pockets which could affect pump prim
ing, the suction line must be as short and direct as
possible. When operation involves a suction lift, the
line must always slope upward to the pump from
the source of the liquid being pumped; if the line
slopes down to the pump at any point along the
suction run, air pockets will be created.
Fittings
Suction lines should be the same size as the pump
inlet. If reducers are used in suction lines, they
should be the eccentric type, and should be in
stalled with the flat part of the reducers uppermost
to avoid creating air pockets. Valves are not nor
mally used in suction lines, but if a valve is used,
install it with the stem horizontal to avoid air pock
ets.

OM-06449PAH SERIES
PAGE B - 3INSTALLATION
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 3‐inch (76,2
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 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).

OM-06449 PAH SERIES
PAGE B - 4 INSTALLATION
Figure 1. 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
This pump is designed with a check valve in the
discharge line.
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.
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

OM-06449PAH SERIES
PAGE B - 5INSTALLATION
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 2).
Figure 2. Aligning Spider‐Type Couplings
Figure 3. Aligning Non‐Spider Type Couplings
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 3).
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.
Drive Belts
When using drive belts, the power source and the
pump must be parallel. Use a straightedge along
the sides of the pulleys to ensure that the pulleys
are properly aligned (see Figure 4). In drive sys
tems 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 4. Alignment of V‐Belt Driven Pumps

OM-06449 PAH SERIES
PAGE B - 6 INSTALLATION
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.
DRIVE BELT TENSIONING
General Rules of Tensioning
For new drive belts, check the tension after 5, 20
and 50 hours of operation and re‐tension as re
quired (see the following procedure for measuring
belt tension). Thereafter, check and re‐tension if re
quired monthly or at 500 hour intervals, whichever
comes first.
Ideal drive belt tension is the lowest tension at
which the belt will not slip under peak load condi
tions. Do not over‐tension drive belts. Over‐ten
sioning will shorten both drive belt and bearing life.
Under‐tensioning will cause belt slippage. Always
keep belts free from dirt, grease, oil and other for
eign material which may cause slippage.

OM-06449
PAh 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 liquids
containing large entrained solids and
slurries. Do not attempt to pump vola
tile, corrosive, or flammable liquids
which may damage the pump or endan
ger personnel as a result of pump fail
ure.
Pump speed and operating condition
points must be within the continuous per
formance range shown on the perfor
mance curve in Section E 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).
The pump will begin to prime upon startup. The air
in the suction line will be discharged from the educ
tor discharge line. Complete priming is indicated
by a positive discharge pressure reading.
If full priming is not achieved, the discharge check
valve may be malfunctioning. If this occurs, shut
down the pump and consult Maintenance and
Repair, Section E for further details.
STARTING
Consult the operations manual furnished with the
power source.
Rotation
The correct direction of pump rotation is counter
clockwise when facing the impeller. The pump
could be damaged and performance adversely af
fected by incorrect rotation. If pump performance
is not within the specified limits (see the curve on
page E‐1), check the direction of power source ro
tation before further troubleshooting.
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 liter
ature supplied with the motor for specific instruc
tions.
Priming
The pump will begin to prime upon startup. The air
in the suction line will be discharged from the educ
tor discharge line. Complete priming is indicated
by a positive discharge pressure reading.
If full priming is not achieved, the discharge check
valve may be malfunctioning. If this occurs, shut
down the pump and consult the separate Mainte
nance and Repair manual for further details.
OPERATION
Leakage
Once the pump is fully primed, no leakage should
be visible at pump mating surfaces, or at pump
connections or fittings. Keep all line connections
and fittings tight to maintain maximum pump effi
ciency.
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.

OM-06449 PAh SERIES
OPERATIONPAGE C - 2
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 immediately and allow it to completely cool
before servicing it. Approach any over‐heated
pump cautiously.
Allow an over‐heated pump to com
pletely cool before servicing. Do not re
move plates, covers, gauges, or fittings
from an overheated pump. Liquid within
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.
As a safeguard against rupture or explosion due to
heat, this pump is equipped with a pressure relief
valve which will open if vapor pressure within the
pump casing reaches a critical point. If over‐heat
ing does occur, stop the pump immediately and al
low it to cool before servicing it. Approach any
over‐heated pump cautiously. It is recom
mended that the pressure relief valve assembly be
replaced at each overhaul, or any time the pump
casing over‐heats and activates the valve. Never
replace this valve with a substitute which has not
been specified or provided by the Gorman‐Rupp
Company.
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. Monitor and record the vacuum suction
gauge readings regularly to detect strainer block
age.
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
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.
Do not operate the pump against a
closed discharge throttling valve for
long periods of time. If operated against

OM-06449
PAh SERIES
OPERATION PAGE C - 3
a closed discharge throttling valve,
pump components will deteriorate, and
the liquid could come to a boil, build
pressure, and cause the pump casing to
rupture or explode.
After stopping the pump, switch off the engine igni
tion and remove the key to ensure that the pump
will remain inoperative.
PERIODIC CHECKS
Seal Cavity And Bearing Lubrication
Both the seal and bearing cavities were fully lubri
cated at the factory. Check the lubrication levels
before startup, and regularly thereafter as indi
cated in Section E, Maintenance and Repair.
When lubrication is required, use only SAE No. 30
non‐detergent oil.
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, Main
tenance and Repair). Bearing overheating can
also be caused by shaft misalignment and/or ex
cessive 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.
Air Compressor
The air compressor was lubricated for test at the
factory. However, always check the lubrication lev
el before startup.
Consult the manual accompanying the air com
pressor and preform all duties and checks as indi
cated.
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.

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.
Discharge check valve contami
nated, damaged, or unable to seat.
Clean or replace check valve.
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.
Leaking or worn seal or pump gasket. Check pump vacuum. Replace
leaking or worn seal or gasket.
Air compressor damaged or belts bro
ken.
Check and repair/replace.
Eductor clogged. Check and clean eductor.
PAh SERIES OM-06449
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 and make
sure pump is cool before opening
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
Impeller or other wearing parts worn
or damaged.
Free impeller of debris.Impeller clogged.
Replace worn or damaged parts.
Check that impeller is properly
centered and rotates freely.
Measure lift w/vacuum gauge. Re
duce lift and/or friction losses in
suction line.
Suction lift too high.
Pump speed too slow. Check driver output; consult driver
operation manual.
Pump speed too high. Check driver output.
Discharge head too low.
Dilute if possible.Liquid solution too thick.
Adjust discharge valve.
Pump or jack shaft bearing(s) frozen. Disassemble, check and replace
bearing(s) as required..
Liquid solution too thick.
Open discharge valve fully to in
crease flow rate, and run engine at
maximum governed speed.
Discharge flow too slow.
Dilute if possible.
Suction check valve or foot valve
clogged or binding.
Clean valve.
Suction intake not submerged at
proper level or sump too small.
Check installation and correct
submergence as needed.
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.
Clean out debris; replace damaged
parts.
Impeller clogged or damaged.
Secure mounting hardware.Pump or drive not securely mounted.
Locate and eliminate source of air
bubble.
Pumping entrained air.
Discharge check valve clogged. Check and clean check valve.
Strainer clogged. Check strainer and clean if neces
sary.
Belt or flexible coupling broken. Check and replace as necessary.
Extreme ambient temperature. Reduce pump output.
Fuel filter clogged. Check & replace often in extreme
operating conditions.
Check and replace as required.Fuel contaminated.
OM-06449 PAh SERIES
TROUBLESHOOTINGPAGE D - 2

TROUBLE POSSIBLE CAUSE PROBABLE REMEDY
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 regu
larly to monitor any increase.
Check belt tension. Adjust as
required.
Excessive tension on drive belt.
PAh SERIES OM-06449
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.