Giant GP5128GB Series Instruction Manual

Contents:
Installation Instructions: page 2
Pump Specications: page 3
Exploded View: page 4
Parts List: page 5
Kits/Torque Specs: page 5
Repair Instructions: page 6
Dimensions: page 7
Warranty Information back page
Model
GP5128GB Series
Triplex Ceramic
Plunger Pump
Operating Instructions /
Manual
GP5128 with External Gearbox and Pinion Drive
GP5128-180 Shown
Updated 04/21

2
INSTALLATION INSTRUCTIONS
Figures for speed (rpm) and pressure apply to
interval operation with cold water.
For continual operation, the speed of all pump
models must be limited to 700 rpm and the
max. operating pressure reduced by 10%.
Required NPSH refers to water: Specic weight
1kg/dm3, viscosity 1°E at max. permissible
revolutions.
Operation and Maintenance
Check oil level prior to starting and ensure
trouble-free water supply. Oil: Use ontly 1.4
gallons (5.4 liters) of Industrial Gear Lube Oil
(Giant p/n 01154) or ISO VG 220 (e.g. Aral
Degol BG220) or SAE 90 gear oil.
Initial change after 50 operating hours and then
every 500 operating hours.
Caution when operating in damp places or
with high temperature uctuations. Oil must
be changed immediately, should condensate
(frothy oil) occur in the gear box.
Keep NPSH under control.
Max. input pressure 145 PSI (10 bar), max.
suction head -4.35 PSI (-0.3 bar).
Safety Rules
Pump operation without safety valve as well
as any excess in temperature or speed limits
automatically voids the warranty. The safety
valve must be regulated in accordance with
the guidelines for liquid spraying units so that
the admissible operating pressure can not be
exceeded by more than 10%.
When the pump is in operation, the open shaft
end must be covered up by a shaft protector
(21), the driven shaft side and coupling by a
contact-protector.
Pressure in discharge line and in pump must
be at zero before any maintenance to the pump
takes place. Close up suction line. Disconnect
fuses to ensure that the driving motor does not
get switched on accidently.
Make sure that all parts on the pressure side of
the unit are vented and relled, with pressure at
zero, before starting the pump.
In order to prevent air, or an air/water-mixture
being absorbed and to prevent cavitation
occuring, te pump-npshr, positive suction head
and water temperature must be kept under
control.
Cavitation and/or compression of gases
lead to uncontrollable pressure-kicks which
can ruin pump and unit parts and also
be dangerous to the operator or anyone
standing nearby.
Giant plunger pumps are suitable for pumping
clean water and other non-agressive or
abrasive media with a specic weight similar to
water.
Before pumping other liquids - especially
inammable, explosive and toxic media
- the pump manufacturer must under all
circumstances be consulted with regard
to the resistance of the pump material.
It is the responsibility of the equipment
manufacturer and/or operator to ensure that
all pertinent safety regulations are adhered
to.
GP5128GB Series Torque Specications/Lubrication Information
Position Item# Description Lubrication Torque Amount
1 13266 Crankcase Molycote Cu-Paste
3 05943 Oil Sight Glass Assembly Loctite 572 22 ft.-lbs. (30 Nm)
10 07008 Inner Hexagon Screw 33 ft.-lbs. (45 Nm)
12 07703 Drain Plug, 3/4” BSP 74 ft.-lbs. (100 Nm)
17 13358 Hexagon Screw 33 ft.-lbs. (45 Nm)
24 13276 Connecting Rod Assembly 22 ft.-lbs. (30 Nm)
31 13284 Radial Shaft Seal Loctite 403
29C 13031 Tension Screw, Plunger Loctite 243 22 ft.-lbs. (30 Nm)
48A 07008 Inner Hexagon Screw, Plug 35 ft.-lbs. (47 Nm)
49 13339 Inner Hexagon Screw, Valve Casing 89 ft.-lbs. (120 Nm)

3
U.S. ......................... (Metric)
Volume.......................................................... 20.6 GPM .............. 78.0 LPM
Discharge Pressure......................................4060 PSI ................. 280 bar
Power Required............................................56.0 BHP................. 41.8 kW
Speed (Continuous)...................................... ................................ 1000 RPM
Inlet Pressure (maximum) ............................-4.35 to145 PSI ...... -0.3 to 10 bar
Plunger Diameter..........................................1.1” .......................... 28 mm
Crankshft Stroke...........................................1.81” ........................ 46 mm
Crankshaft Diameter.....................................1.38” ........................ 35 mm
Crankshaft Mounting ..................................................................... Either side
Shaft Rotation................................................................................ Top of pulley towards manifold
Temperature of Pumped Fluids ....................Up to 140oF ............. (60oC)
Inlet Ports ...................................................................................... (3) 1-1/2” NPT
Discharge Ports............................................................................. (2) 1” NPT
Weight ..........................................................179 lbs. ................... (81 kg)
Crankcase Oil Capacity................................1.2 Gal. ................... (4.6 liter)
Fluid End Material......................................... ................................ Nickel-Plated Spheroidical Cast Iron
Specications
Model GP5128GB Series
Consult the factory for special requirements that must be met if the pump is to
operate beyond one or more of the limits specied above.
Horsepower Ratings:
We recommend a 1.15 service factor be specied when selecting an electric motor as the power
source.
To compute electric motor horsepower required, use the following formula: HP = (GPM X PSI) /
1450.
The formula to determine the horsepower required for a gas engine is: HP = (GPM X PSI) / 1150.
The formula to determine the horsepower required for a diesel engine is: HP = (GPM X PSI) / 1250.
For the Application of a Hydraulic Motor:
To Determine the Torque of a Hydraulic Motor -- (GPM x PSI x 36.77) / RPM = Torque (in-lbs)
Calculating RPM / GPM of Pump:
A pump must be connected to an electric motor or gas or diesel engine with the correct ratio of pulleys
and belts to attain the required speed and GPM. The use of a Variable Frequency Drive (VFD) may
also
be used to control the RPM of a properly sized electric motor when variable ows are required.
(Max. Pump RPM / Rated Pump GPM) x Required Pump GPM = Required Pump RPM
To calculate a pulley diameter one (1) pulley diameter and the required pump RPM must be known:
(Pump RPM x Pump Pulley Diameter) / Motor RPM = Motor Pulley Diameter
(Motor RPM x Motor Pulley Diameter) / Pump RPM = Pump Pulley Diameter

4
GP5128GB Series Exploded View
GP5128-180 Shown

5
ITEM PART DESCRIPTION QTY.
1 03248 Crankcase 1
2 13000 Oil Filler Plug Assembly 1
3 05943 Oil Sight Glass Assembly 1
4 13267 Crankcase Cover 1
5 13268 O-Ring 1
8 07105 Oil Dip Stick Assembly 1
9 01009 O-Ring, Dip Stick 1
10 07008 Inner Hexagon Screw 8
11 06725 Spring Washer 8
12 07703 Drain Plug, 3/4” BSP 1
13 07704 Gasket, Drain Plug 1
14 03249 Bearing Cover 1
14A 03250 O-Ring 4
15 08439 Lid 1
16 08380 O-Ring 1
20 13206 Taper Roller Bearing 2
20A* 13207 Shim, 0.1mm 1-5
20B* 04723 Shim, 0.15mm 1-5
20C* 04724 Shim, 0.2mm 1-5
22 03251 Crankshaft 1
23 03252 Fitting Key 1
24 13276 Connecting Rod Assembly 3
25 13279 Crosshead Assembly 3
28 13281 Crosshead Pin 3
29A 07125 Centering Sleeve 3
29B 13220 Plunger Pipe 3
29C 13031 Tensioning Screw 3
29D 07755 Copper Ring 3
30 13282 Oil Scraper 3
30A 05889 Washer for Drip Shield 3
31 13284 Radial Shaft Seal 3
35 04286 Seal Sleeve 3
35B 08183 O-Ring 3
36 13228 Grooved Ring 3
37 04287 Seal Case 3
37A 07700 O-Ring 6
39 13197 Pressure Ring 3
40 13115 V-Sleeve 6
41 13198 Sleeve Support Ring 3
42 07173 Tension Spring 3
*May not be present in quantities stated
GP5128GB Series Spare Parts List
ITEM PART DESCRIPTION QTY.
43 04288-NPT Valve Casing 1
44 07150 O-Ring 6
45 07109 Plug, 1/2” BSP 1
45A 06272 Copper Seal Ring, 1/2” 1
46 07060 Valve Assembly 6
46A 07064 Valve Seat 6
46B 07063 Valve Plate 6
46C 07062-0100 Valve Spring 6
46D 07066 Spacer Pipe 6
47 04295 Spacer Ring 3
48 04289 Plug 3
48A 07008 Inner Hexagon Screw 12
48B 13012 O-Ring 3
48C 06078 Tension Spring 3
49 13339 Inner Hexagon Screw 8
54 06626 Plug, 1” NPT 1
55 06627 Plug, 1-1/2” NPT 2
56 07623 Eye Bolt 1
57 03256 Gearbox Assembly (58-79) 1
58 03257 Bottom Casing for Gear 1
59 03195 Top Casing for Gear 1
60 03196 O-Ring 1
61 03253 Centering Ring 1
62 03254 Gearwheel Set 2.0:1 1
64 03199 Cylinder Roller Bearing 1
65 03200 Cylinder Roller Bearing 1
66 03201 Shim, 0.1 mm 1-3
67 05058 Radial Shaft Seal 1
68 04744 Cylindrical Pin 3
69 03202 Hexagon Socket Screw 8
70 03255 Spacer Ring for Gear 1
71 07008 Hexagon Socket Screw 4
72 08041 Washer 8
73 08380 O-Ring 1
75 13362 Disc for Crankshaft 1
76 13358 Hexagon Screw 1
77 07109 Plug, 1/2” BSP 2
78 06272 Copper Seal Ring, 1/2” 2
79 13243 Fitting Key 1
GP5128GB Series Repair Kits
Plunger Packing Kit - #09761
Item Part# Description Qty.
35B 08183 O-Ring 3
36 13228 Grooved Ring 3
37A 07700 O-Ring 6
40 13115 V-Sleeve 6
Valve Assembly Kit - #09762
Item Part # Description Qty.
46 07060 Valve Assembly 6
48B 13012 O-Ring 3
Oil Seal Kit - #09230
Item Part # Description Qty.
31 13284 Oil Seal 3
GP5128-180 Shown

6
To Check Valves
Remove inner hexagon screw (48A) and remove plugs (48) with a screwdriver. Check O-rings on plugs (48B). Pull out
tension spring (48C). Using a clipring pliers or a ø22 extractor tool, remove valve assembly (46) out of the valve casing (43).
Remove the next exposed spacer pipe and suction valve assembly as already described. Remove the valve seats (46A)
from the spacer pipes by lightly tapping the valve plate (46B) from above with a plastic rod. Check sealing surfaces and
replace worn parts. When reassembling, use new O-rings (44/48B) and lightly oil them before installing.
Tighten inner hexagon screws (48A) to 35 Ft-Lbs (47NM).
To Check Seals and Plunger Pipe
Loosen the 8 inner hexagon screws (49) and pull o󰀨 valve casing (43) to the front. Pull seal sleeves (35) out of guides in
crankcase (1) and over the plunger pipe (29B). Pull support ring (41), sleeves (40) and pressure ring (39) out of seal sleeve.
Check plunger surfaces, sleeves (40) and grooved rings (36). Replace worn parts.
If the plunger pipe is worn out, loosen tension screw (29C) and remove plunger pipe. Clean contact surfaces of plunger (25)
thoroughly. Then carefully place new plunger pipe through the oiled seals (40) into the seal case (35). Check O-rings (35B)
on seal sleeves and replace worn O-rings. Then push seal sleeve together with plunger pipe into the crankcase guide. Turn
gear carefully until plunger (25) comes up against the plunger pipe. Put a new copper gasket (29D) onto the tension screw
(29C). Cover the thread of tension screw and the gasket with Loctite 243 and tighten to 22 Ft.-lbs. (30 NM).
Important! Care must be taken that no glue gets between the plunger pipe (29B) and the centering sleeve (29A). The plunger
pipe should not be strained by eccentric tightening of the tension screw or through damage to front of surface of plunger,
otherwise it will probably break. Tighten the inner screws (49) for the valve casing evenly to 89 Ft.-Lbs. (120 NM).
To Dismantle Gear
As described above, remove valve casing (43) and plunger pipe (29B), drain the oil. Remove the gear cover (4) and
bearing cover (14). Loosen connecting rod screws (24A) and push the front of the connecting rod (24) forward as
far as possible into the crosshead guide.
IMPORTANT! Connecting rods (24) are marked for identication. Do not twist connecting rod halves. Connecting
rod is to be reinstalled in the same position on shaft journals.
IMPORTANT! Do not bend the connecting rod (24) shanks. Check crankshaft (22) and connecting rod (24)
surfaces, radial shaft seals (15) and taper roller bearings (20).
To remove the oil seals (31) use a wooden rod and sharply hit down on the oil seals from the crankcase (1).
Note: when replacing the oil seals, apply a small amount of locktight to the outside edges of each oil seal before
reinserting them into the crankcase.
To Dismantle Reduction Gear
Remove screws (69). Remove bottom casing (58); it may be necessary to use a rubber mallet. Remove screw (76)
and disc (75). Pull gear wheel (62) o󰀨 of the shaft. Remove screws (71), top casing (58) and centering ring (61).
Turning the crankshaft (22) slightly, hit it out carefully to the side with a rubber hammer.
To Reassemble
Using a soft tool, press in the outer bearing ring until the outer edge lines up with the outer edge of the bearing
hole. Remove bearing cover (14) together with radial shaft seal (15) and o-ring (16). Fit crankshaft (22) through
bearing hole on the opposite side. Press in outer bearing and tighten it inwards with the bearing cover, keeping the
crankshaft in vertical position and turning slowly so that the taper rollers of the bearings touch the edge of the outer
bearing ring. Adjust axial bearing clearance to at least 0.1mm and maximum 0.15mm by placing tting discs (20A,
20B and 20C) under the bearing cover.
IMPORTANT! After assembly has been completed, the crankshaft should turn easily with very little clearance.
Tighten connecting rod screws (24A) to 22 ft.-lbs. (30 Nm) Re-assemble the uid end (see instructions above).
If cylinder roller bearing (65) was removed, heat them up (before pressing onto the pinion shaft). Slightly press
the gearwheel (62) onto the crankshaft (22) so that remaining portion of the gearwheel set can be positioned in
the correct manner. Carefully, tap the gearwheel and the pinion (simultaneously) onto the crankshaft and into the
bearing seat. Reassemble remaining gearbox parts making sure not to damage the radial shaft seal (67) or the
o-ring (60).
IMPORTANT! Before putting the pump into operation, turn the reduction gear (by hand) at least four times in each
direction (to ensure proper alignment).
Reassemble shaft cover (14) and crankcase cover (4) and properly torque screws (17
& 10).
IMPORTANT! The 1/2” BSP connection in the crankcase serves the purpose of draining
leakage water. The connection should not be closed (see the drawing to the right).
GP5128GB Series Repair Instructions

7
GP5128GB Series Dimensions Inches (mm)
GP5128GB Shown
GP5128GB-90 Shown
GP5128GB-180 Shown

GIANT INDUSTRIES, INC.,
900 N. Westwood Ave., Toledo, Ohio 43607
Phone [phone], FAX [phone],
www.giantpumps.com
© Copyright 2021 Giant Industries, Inc. 04/21 GP5128GB Series.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. Five (5) years from the date of shipment for all pumps used in portable pressure
washers with NON-SALINE, clean water applications.
2. Two (2) years from the date of shipment for Giant pumps used in car wash
applications.
3. One (1) year from the date of shipment for all other Giant industrial and consumer
pumps.
4. Six (6) months from the date of shipment for all rebuilt pumps
5. 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 workmanship 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 warranty 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 WARRANTIES OR MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE AND ALL SUCH WARRANTIES ARE HEREBY DISCLAIMED AND
EXCLUDED BY THE MANUFACTURER.
WARNING: This product might contain a chemical known to the State of California to
cause cancer, and birth defects or other reproductive harm.
For more information go to www.P65Warnings.ca.gov