Giant LP122A Series User manual

Models
LP122A/LP123/LP255
Triplex Ceramic
Plunger Pump
Operating Instructions/
Repair and Service Manual
Contents:
Installation Instructions: page 2
Pump Specications - LP122A page 3
Pump Specications - LP123: page 3
Exploded View: page 4
Parts List/Kits: page 5
Pump Specications - LP255: page 6
Troubleshooting Guide: page 7
Suggested Maintenance Schedule: page 7
Repair Instructions/Torque Specs.: pages 8-10
Dimensions: page 11
Warranty Information: back pageUpdated 5/12

2
NOTE: Contact Giant Industries for Service School Information.
Phone: [phone]
INSTALLATION INSTRUCTIONS
Installation of the Giant Industries, Inc., pump is
not a complicated procedure, but there are some
basic steps common to all pumps. The following
information is to be considered as a general out-
line for installation. If you have unique require-
ments, please contact Giant Industries, Inc. or
your local distributor for assistance.
1. The pump should be installed at on a base to a
maximum of a 15 degree angle of inclination to en-
sure optimum lubrication.
2. The inlet to the pump should be sized for the ow
rate of the pump with no unnecessary restrictions that
can cause cavitation. Teon tape should be used to
seal all joints. If pumps are to be operated at temper-
atures in excess of 1600F, it is important to insure a
positive head to the pump to prevent cavitation. See
NPSH curve for LP122A Series/LP123 pumps.
3. The discharge plumbing from the pump should be
properly sized to the ow rate to prevent line pres-
sure loss to the work area. It is essential to provide a
safety bypass valve between the pump and the work
area to protect the pump from pressure spikes in the
event of a blockage or the use of a shut-off gun.
Finally, remember that high pressure operation in a pump system has many advantages. But, if it is used carelessly
and without regard to its potential hazard, it can cause serious injury.
IMPORTANT OPERATING CONDITIONS
Failure to comply with any of these conditions invalidates the warranty.
1. Prior to initial operation, add oil to the crankcase so that oil level is between the two lines on the oil dipstick. DO
NOT OVERFILL.
Use SAE 90 Industrial gear oil (Giant’s p/n 01154)
Crankcase oil should be changed after the rst
50 hours of operation, then at regular intervals of 500
hours or less depending on operating conditions.
2. Pump operation must not exceed rated pressure,
volume, or RPM. A pressure relief device must be
installed in the discharge of the system.
4. Use of a dampener is necessary to minimize
pulsation at drive elements, plumbing, connections,
and other system areas. The use of a dampener with
Giant Industries, Inc. pumps is optional, although
recommended by Giant Industries, Inc. to further re-
duce system pulsation. Dampeners can also reduce
the severity of pressure spikes that occur in systems
using a shut-off gun. A dampener must be positioned
downstream from the unloader.
5. Crankshaft rotation on Giant Industries, Inc. pumps
should be made in the direction designated by the
arrows on the pump crankcase. Reverse rotation
may be safely achieved by following a few guidelines
available upon request from Giant Industries, Inc.
Required horsepower for system operation can be
obtained from the charts on pages 3 and 6.
6. Before beginning operation of your pumping
system, remember: Check that the crankcase and
seal areas have been properly lubricated per recom-
mended schedules. Do not run the pump dry for ex-
tended periods of time. Cavitation will result in severe
damage. Always remember to check that all plumbing
valves are open and that pumped media can ow
freely to the inlet of the pump.
3. Acids, alkalines, or abrasive uids cannot be
pumped unless approval in writing is obtained before
operation from Giant Industries, Inc.
4. Run the pump dry approximately 10 seconds to
drain the water before exposure to freezing tempera-
tures.
LP122A/LP123
NPSHR Curve

3
Specications
Models LP122A/LP123
*Pump speeds of 640 RPM and above require a minimum inlet pressure of 12 psig.
**Pump speeds of 805 RPM and above require a minimum inlet pressure of 14 psig.
U.S..................................(Metric)
Volume (Continuous) .................................... 35.4 GPM ........................ (134 l/m)
Volume (Intermittent) .................................... 40 GPM ........................... (151.4 l/m)
Discharge Pressure (Continuous) ................. 1300 PSI ......................... (90 Bar)
Discharge Pressure (Intermittent) .................2000 PSI ......................... (138 Bar)
Inlet Pressure ................................................ Up to 90 PSI .................... (Up to 6.2 Bar)
Speed (Continuous) ............................................................................... Up to 800 RPM*
Speed (Intermittent) ............................................................................... Up to 885 RPM**
Plunger Diameter ..........................................1.65” ................................ (42 mm)
Stroke ........................................................... 1.65” ................................ (42 mm)
Crankcase Oil Capacity ................................ 116 .oz. .......................... (3.43 liters)
Temperature of Pumped Fluids ..................... Up to 140oF ..................... (Up to 60oC)
Inlet Ports ............................................................................................... 2 x 1-1/2” NPT
Discharge Ports ..................................................................................... 2 x 1” NPT
Crankshaft Mounting .............................................................................. Either Side
Shaft Rotation ............................................... Top of Pulley Towards Fluid End
Weight ........................................................... 125 lbs. ........................... (57 Kg)
Crankshaft Diameter .....................................1.38” ................................ (35 mm)
Valve Casing - LP122A .......................................................................... Aluminum Bronze
Valve Casing - LP123 ............................................................................ Brass
Volumetric Efciency @ 800 RPM ......................................................... 0.96
Mechanical Efciency @ 800 RPM ....................................................... 0.85
PULLEY INFORMATION
Pulley selection and pump speed are based on a
1725 RPM motor and “B” section belts. When se-
lecting desired GPM, allow for a ±5% tolerance on
pumps output due to variations in pulleys, belts and
motors among manufacturers.
1. Select GPM required, then select appropriate-
motor and pump pulley from the same line.
2. The desired pressure is achieved by selecting
the correct nozzle size that corresponds with the
pump GPM.
*Intermittent duty only! - Consult factory!
HORSEPOWER INFORMATION
We recommend that a 1.15 service factor be
specied when s electing an electric motor as
the power source. To compute specic pump
horsepower requirements, use the following
formula:
HP = (GPM X PSI) / 1450
LP122A/LP122A-4000/LP123 PULLEY SELECTION AND HORSEPOWER
REQUIREMENTS
GPM
PUMP
PULLEY
MOTOR
PULLEY
RPM 600 PSI 800 PSI 1000 PSI 1300 PSI 2000 PSI*
22.3 12.75" 3.95" 500 9.6 12.7 15.9 20.7 31.9
24.7 12.75" 4.35" 555 10.6 14.1 17.6 22.9 35.3
28.5 12.75" 4.95" 640 12.2 16.3 20.4 26.5 40.7
30.9 12.75" 5.35" 695 13.2 17.7 22.1 28.7 44.1
33.4 12.75" 5.75" 750 14.3 19.1 23.9 31.0 47.7
35.6 12.75" 6.15" 800 15.3 20.3 25.4 33.1 50.9
39.4 12.75" 6.50" 885* 16.9 22.5 28.1 36.6 56.3

4
Exploded View - LP122A/LP123/LP255

5
Item Part # Description Qty.
1 07759 Crankcase 1
2 13000 Oil Filler Plug 1
3 15940 Cover Plate (A) 1
3A 07223-0100 Spring Washer (A) 2
3B 05051 Hexagon Screw (A) 1
4 06085 Crankcase Cover 1
5 07104 O-Ring 1
6 05943 Oil Sight Glass W/Gasket (A) 1
6 07186 Oil Sight Glass W/Gasket(B, C) 1
8 06086 Oil Dipstick 1
9 01009 O-Ring 1
10 01010 Screw 4
11 01011-0400 Spring Washer, (A, B) 5
12 07109 Oil Drain Plug 1
13 07182 Gasket 1
14 07111 Bearing Cover 2
15 07112 Crankshaft Seal 2
16 07113 O-Ring 2
17 07114 Hex Screw 8
20 07116 Taper Roller Bearing 2
20A 07117 Fitting Disc, 0.1mm 1
20B 13001 Fitting Disc, 0.15mm 2
20C 04091 Shim 3
21 05376 Shaft Protector 1
21A 05377 Shaft Guard Holder 1
22 13242 Crankshaft 1
23 13243 Key 1
24 13340 Connecting Rod Assy. 3
24A 13277 Hex Screw 6
24B 13278 Spring Washer 6
25 13341 Crosshead Plunger Base Assy. 3
28 13232 Crosshead Pin 3
29A 07735 Centering Sleeve 3
29B 07736 Plunger Pipe (A, B) 3
29B 13022 Plunger Pipe (C) 3
29C 07737 Plunger Bolt 3
29D 07755 Copper Gasket 3
29E 06087 Spacer Pipe 3
30 07779 Flinger 3
Item Part # Description Qty.
31 07133 Radial Shaft Seal 3
35 13342 Seal Sleeve, (A, B) 3
35 06699 Seal Sleeve (C) 3
35A 07740 O-Ring 3
35B 13141 O-Ring (C) 3
36 13415 V-Sleeve, Weep (A, B) 3
36 13025 V-Sleeve, Weep (C) 3
36A 13416A Pressure Ring, Weep, (A, B) 3
36A 06700 Pressure Ring (C) 3
36B 06174 Drip Shield (A, B) 3
37 06701 Support Disc (C) 3
39 07744 Pressure Ring, (A, B) 3
39 13026 Pressure Ring (C) 3
40 07745 V-Sleeve (A, B) 6
40 13027 V-Sleeve (C) 6
41 07746 Support Ring, (A, B) 3
41 06702 Support Ring (C) 3
43 13343 Valve Casing, (A) 1
43 06703 Valve Casing, (B, C) 1
44 07748 Valve Seat 6
44A 07150 O-Ring 6
45 07749 Valve Plate 6
46 07750 Valve Spring 6
46A 07751 Valve Assy. Complete
(#44, 44A, 45, 46, & 47) 6
47 07752 Spring Retainer 6
48 07753 Plug, (A) 6
48 06504 Plug, (B, C) 6
48A 12055 O-Ring 6
49 07157 Stud Bolt 8
49A 07158 Nut 8
49B 07159 Washer 8
50 07423 Plug, (A, B, C) 1
50A 07161 Gasket 1
52 13020 Disk for Crankshaft 1
53 06607 Hexagon Screw 1
54 07756 Plug 1” NPT, (A) 1
54 06626 Plug 1” NPT, (B, C) 1
55 07757 Plug 1-1/2” NPT, (A) 1
55 06627 Plug, 1-1/4” NPT, (B, C) 1
LP122A/LP123/LP255 PARTS LIST
A = LP122A B = LP123 C = LP255
LP122A/LP123/LP255 PUMP REPAIR KITS
Plunger Packing Kits
# 09477 (LP122A, LP123)
(for pumps manufatured after 4/98)
Item Part # Description Qty.
35A 07740 O-ring 3
36 13415 V-Sleeve, Weep 3
40 07745 V-Sleeve 6
# 09535 (LP255)
Item Part # Description Qty.
35A 07740 O-ring 3
35B 13141 O-ring 3
36 13025 V-Sleeve weep 3
40 13027 V-Sleeve 6
Valve Assembly Kit - #09136
Item Part # Description Qty.
46A 07751 Valve Assembly, Complete 3
48A 12055 O-ring 3
Oil Seal Kit - #09577
Item Part # Description Qty.
31 07133 Radial Shaft Seal 3
NOTE: For LP122 pumps manufactured prior to 5/94, which need weep seal replacement, change the pressure ring
(36) to the newer style (p/n 13416) and use the new style weep seal (p/n 13415) in your pumps.

6
Specications
Model LP255
U.S. (Metric)
Volume .......................................................... 26.0 GPM ........................ (98 l/min)
Discharge Pressure ...................................... 2175 PSI ......................... 150 Bar)
Inlet Pressure ................................................ Up to 90 PSI .................... Up to 6.2 Bar)
Speed .................................................................................................... Up to 1000 RPM
Plunger Diameter .......................................... 1.26” ................................ (32 mm)
Stroke ........................................................... 1.65” ................................ (42 mm)
Crankcase Oil Capacity ................................ 116 .oz. .......................... (3.43 liters)
Temperature of Pumped Fluids ..................... Up to 140oF ..................... (60 oC)
Inlet Ports ............................................................................................... 2 x 1-1/2” NPT
Discharge Ports ..................................................................................... 2 x 1” NPT
Crankshaft Mounting .............................................................................. Either Side
Shaft Rotation ............................................... Top of Pulley Towards Fluid End
Weight ........................................................... 125 lbs. .......................... (57 Kg)
Crankshaft Diameter ..................................... 1.38” ................................ (35 mm)
Valve Casing .......................................................................................... Brass
Volumetric Efciency @ 800 RPM ......................................................... 0.96
Mechanical Efciency @ 800 RPM ....................................................... 0.85
PULLEY INFORMATION
Pulley selection and pump speed are based on
a 1725 RPM motor and “B” section belts. When
selecting desired GPM, allow for a ±5% tolerance
on pumps output due to variations in pulleys, belts
and motors among manufacturers.
1. Select GPM required, then select appropriate
motor and pump pulley from the same line.
2. The desired pressure is achieved by select-
ing the correct nozzle size that corresponds
with the pump GPM.
HORSEPOWER INFORMATION
We recommend that a 1.15 service factor be
specied when s electing an electric motor as
the power source. To compute specic pump
horsepower requirements, use the following
formula:
HP = (GPM X PSI) / 1450
LP255 PULLEY SELECTION AND HORSEPOWER REQUIREMENTS
PUMP
PULLEY
MOTOR
PULLEY
RPM GPM 1000 PSI 1500 PSI 2000 PSI 2175 PSI
12.75" 3.95" 500 13 9.0 13.5 18.1 19.6
12.75" 4.35" 640 16.6 11.5 17.3 23.1 25.1
12.75" 4.95" 750 19.5 13.5 20.3 27.1 29.5
12.75" 5.35" 805 20.9 14.5 21.8 29.0 31.6
12.75" 5.75" 865 22.5 15.6 23.4 31.3 34.0
12.75" 6.15" 920 23.9 16.6 24.9 33.2 36.1
12.75" 6.50" 1000 26 18.1 27.1 36.1 39.3

Preventative Maintenance Check-List & Recommended Spare Parts List
Check Daily Weekly 50hrs Every Every Every
500 hrs 1500 hrs 3000 hrs
Oil Level/Quality X
Oil Leaks X
Water Leaks X
Belts, Pulley X
Plumbing X
Recommended Spare Parts
Oil Change (1 Gallon) p/n 1154 X X
Seal Spare Parts (1 kit/pump) X
(See page 5 for kit list)
Oil Seal Kit (1 kit/pump) X
(See page 5 for kit lit)
Valve Spare Parts (1 kit/pump) X
(See page 5 for kit list)
7
PUMP SYSTEM MALFUNCTION
MALFUNCTION CAUSE REMEDY
The Pressure and/ Worn packing seals Replace packing seals
or the Delivery Broken valve spring Replace spring
Drops Belt slippage Tighten or Replace belt
Worn or Damaged nozzle Replace nozzle
Fouled discharge valve Clean valve assembly
Fouled inlet strainer Clean strainer
Worn or Damaged hose Repair/Replace hose
Worn or Plugged relief valve on pump Clean, Reset, and Replace worn parts
Cavitation Check suction lines on inlet of
pump for restrictions
Unloader Check for proper operation
Water in crankcase High humidity Reduce oil change interval
Worn seals Replace seals
Noisy Operation Worn bearings Replace bearings, Rell crankcase
oil with recommended lubricant
Cavitation Check inlet lines for restrictions
and/or proper sizing
Rough/Pulsating Worn packing Replace packing
Operation with Inlet restriction Check system for stoppage, air
Pressure Drop leaks, correctly sized inlet
plumbing to pump
Accumulator pressure Recharge/Replace accumulator
Unloader Check for proper operation
Cavitation Check inlet lines for restrictions
and/or proper size
Pressure Drop at Gun Restricted discharge plumbing Re-size discharge plumbing to
ow rate of pump
Excessive Worn plungers Replace plungers
Leakage Worn packing/seals Adjust or Replace packing seals
Excessive vacuum Reduce suction vacuum
Cracked plungers Replace plungers
Inlet pressure too high Reduce inlet pressure
High Crankcase Wrong Grade of oil Giant oil is recommended
Temperature Improper amount of oil in crankcase Adjust oil level to proper amount

8
LP122A/LP123/LP255 - Repair Instructions
1. With a 30mm wrench, re-
move the six (6) plugs (48)
from the valve casing (43).
Inspect the O-rings (48A)
and replace if necessary.
Remove the complete
valve assembly (46A) by
threading a 12mm bolt
intothespringretainerand
pulling straight out.
2. To disassemble the valve, screw the bolt into the retainer until
the valve plate (45) presses the valve seat (44) out of the
spring retainer. Examine all parts and replace if necessary.
If the seat doesn’t come out, use a valve puller to remove.
3. Remove the eight (8) hex
nuts (49A) with a 19mm
wrench. Tap the back of
the manifold (43) with a
rubber mallet to dislodge
and slide off the studs.
4. Remove the seal sleeve (35) from the manifold and/or
crankcase. Remove the pressure rings (39&36A), drip shield
(36B for LP122A & LP123 only), v-sleeves (40&36), support
ring (41) and O-rings (35A and 35B in LP255A only) from
the manifold and seal sleeve, respectively. For LP255 only,
remove support ring (37). Examine seals carefully and re-
place if worn. Clean all parts.
6. Inspect surface of plunger pipe (29B) carefully. Remove
any chemical or mineral deposits taking care not to dam-
age the surface of the plunger. If plunger pipe is worn,
remove the plunger bolt (29C) , plunger pipe (29B) and
spacer (29E). Replace worn parts necessary. Note: Al-
ways use a new copper gasket (29) when repairing the
plunger assembly.
5. If there are signs of oil
leaking through the
plunger oil seals, then re-
placment is neccessary.
Dissassemble the gear
end and push out the
seals from the back of
the pump. 29E 29A 29B 29D 29C
36A 36B 36 35 35A 35B 39 40 40 41 37
(LP122A & LP123 only) (LP255 only) (LP255 only)
44A 44 45 48 47

9
7. If previously disassembled thoroughly clean all exposed surfaces on the
spacer (29E) and all exposed threads on the plunger bolt (29C) and the
steel plunger base (25). Threads MUST be free of old loc-tite and any other
material such as oil, grease, etc. This is necessary to ensure proper curing
of new loc-tite. Giant recommends cleaning the threads with acetone or
other suitable cleaner. Reassemble plunger assembly parts (29A, 29B, &
29E) using a new copper gasket (29D) and the cleaned plunger bolt (29C).
Slide the bolt through the center of the four (4) pieces so that the threaded
end is exposed. Apply several drops of loc-tite 243 (or equivalent) adhesive
to the threads. Thread into steel plunger base and tighten to 26 ft.-lbs. (35
Nm). BE CERTAIN ALL PARTS ARE CENTERED WITH THE BOLT!
TO REASSEMBLE PROCEED AS FOLLOWS:
29E 29A 29B 29D 29C
LP122A/LP123/LP255 - Repair Instructions
8. Lubricate weep seal (36). Place, weep seal (36), and pressure
ring (36A) into the seal sleeve (35). Assemble the O-ring (35A
and 35B for LP255 only) onto seal sleeve and lubricate.
9. For LP255 pumps, in-
sert support ring (37) into
valve casing (43). Place
support ring (41) and
v-sleeves (40) into valve
casing.
36A 36B 36 35 35A 35B 39
(LP122A & LP123 only) (LP255 only)
10. Place entire manifold/seal
sleeve assembly over the
studs and push rmly until
seated against the crank-
case.
11. Tighten hex nuts (49A) in a
crosswise pattern (shown
above) to 60 ft.-lbs. (81
Nm).
647
8135
2

10
13. Replace plug with O-ring (48,
& 48A) and tighten to 160
ft.-lbs. (217 Nm).
12. Next, place valve assemblies
(46A) into manifold after rst
lubricating the O-ring (44A).
Seat rmly into manifold.
14. Fill crankcase with approxi-
mately 116 uid ounces of
Giant oil or equivalent SAE 90
industrial gear oil and check
oillevelofthecrankcasewith
the dipstick. Proper level is
center of two lines. Reinstall
your Giant LP pump into your
system.
Contact Giant Industries or your local distributor for mainte-
nance of the gear end of your pump. Phone: [phone]
Contact Giant Industries for service school information.
Phone: [phone]
LP122A/LP123/LP255 TORQUE SPECIFICATIONS
Item # Part # Description Torque Amount
10 01010 Screw, Cover 125 in.-lbs. (14 Nm)
17 07114 Hex Screw, Bearing Cover 125 in.-lbs. (14 Nm)
24A 13277 Hex Screw, Connecting Rod 250 in.-lbs. (28 Nm)
29C 07737 Plunger Bolt 26 ft.-lbs. (35 Nm)
48 06504/07753 Plug, Valve 160 ft.-lbs. (217 Nm)
49A 07158 Nut, Stud Bolt 60 ft.-lbs. (81 Nm)
LP122A/LP123/LP255 - Repair Instructions

11
LP122A/LP123/LP255 Dimensions (mm)

GIANT INDUSTRIES, INC., 900 N. Westwood Avenue, P.O. Box 3187, Toledo, OH 43607
PHONE: [phone], FAX: [phone], www.giantpumps.com
 Copyright 2012 Giant Industries, Inc.
05/12 LP122A_LP123_LP255.indd
GIANT INDUSTRIES LIMITED WARRANTY
Giant Industries, Inc. pumps and accessories are warranted by the manufacturer to be free from
defects in workmanship and material as follows:
1. For portable pressure washers and self-serve car wash applications, the discharge
manifolds will never fail, period. If they ever fail, we will replace them free of charge.
Our other pump parts, used in portable pressure washers and in car wash applications,
are warranted for ve years from the date of shipment for all pumps used in NON-
SALINE, clean water applications.
2. One (1) year from the date of shipment for all other Giant industrial and consumer
pumps.
3. Six (6) months from the date of shipment for all rebuilt pumps.
4. Ninety (90) days from the date of shipment for all Giant accessories.
This warranty is limited to repair or replacement of pumps and accessories of which
the manufacturer’s evaluation shows were defective at the time of shipment by the manufacturer.
The following items are NOT covered or will void the warranty:
1. Defects caused by negligence or fault of the buyer or third party.
2. Normal wear and tear to standard wear parts.
3. Use of repair parts other than those manufactured or authorized by Giant.
4. Improper use of the product as a component part.
5. Changes or modications made by the customer or third party.
6. The operation of pumps and or accessories exceeding the specications set forth
in the Operations Manuals provided by Giant Industries, Inc.
Liability under this warranty is on all non-wear parts and limited to the replacement or repair of those
products returned freight prepaid to Giant Industries which are deemed to be defective due to work-
manship or failure of material. A Returned Goods Authorization (R.G.A.) number and completed
warranty evaluation form is required prior to the return to Giant Industries of all products under war-
ranty consideration. Call (419)-531-4600 or fax [phone] to obtain an R.G.A. number.
Repair or replacement of defective products as provided is the sole and exclusive remedy provided
hereunder and the MANUFACTURER SHALL NOT BE LIABLE FOR FURTHER LOSS, DAMAGES,
OR EXPENSES, INCLUDING INCIDENTAL AND CONSEQUENTIAL DAMAGES DIRECTLY OR
INDIRECTLY ARISING FROM THE SALE OR USE OF THIS PRODUCT.
THE LIMITED WARRANTY SET FORTH HEREIN IS IN LIEU OF ALL OTHER WARRANTIES OR
REPRESENTATION, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY WAR-
RANTIES OR MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE AND ALL SUCH
WARRANTIES ARE HEREBY DISCLAIMED AND EXCLUDED BY THE MANUFACTURER.