A German-made reciprocating triplex plunger pump.

Spheroidal cast iron crankcase with sight glass and vented dipstick; forged, through-hardened, ground and polished crankshaft; bronze connecting rods; hardened stainless steel plunger bases; solid ceramic plungers; nitrile seals with fabric reinforcing; stainless steel valves and nickel-plated Spheroidal cast iron manifold.

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

  • GP7255A-5000 Exploded View
  • GP7255A-5000 Parts List
  • Giant Industries Limited Warranty
  • GP7255A-5000 Installation Instructions
  • GP7255A-5000 Repair Instructions
  • Troubleshooting Guide


U.S. Metric
Flow 65.8 GPM 250 L/min
Maximum Discharge Pressure 1500 PSI 100 bar
Crankshaft Speed 700 RPM
Maximum Inlet Pressure 145 PSI 10 bar
Maximum Temperature 140 °F 60 °C
Plunger Diameter 2.17″ 55 mm
Stroke 2.05″ 52 mm
Crankshaft Diameter 48 mm
Crankshaft Rotation Top of Pulley Towards Manifold
Key Width 0.6″ 14 mm
Crankshaft Mounting Either Side
Inlet Ports (2) 2-1/2″ BSP
Discharge Ports (2) 1-1/4″ BSP
Crankcase Oil Capacity 1.9 gal 7.3 L
Weight 474 lbs. 215 kg
Key Component Material
Manifold Stainless Steel
Plungers Solid Ceramic Oxide
Valves Stainless Steel
Seals Nitrile with Fabric Reinforcing
Gear End Spheroidal Cast Iron

Click the image to enlarge


RPM GPM 800 PSI 1000 PSI 1300 PSI 1500 PSI
479 45.0 24.8 31.0 40.3 46.6
531 49.9 27.5 34.4 44.7 51.6
585 55.0 30.3 37.9 49.3 56.9
638 60.0 33.1 41.4 53.8 62.1
700 65.8 36.3 45.4 59.0 68.1

Horsepower Requirements

The ratings shown are the power requirements for the pump. Gas engine power outputs must be approximately twice the pump power requirements shown above.

We recommend a 1.15 service factor be specified when selecting an electric motor as the power source. To compute specific pump horsepower requirements use the following formulas:
Electric HP = (GPM X PSI)/1450
Gas HP = (GPM X PSI)/1100

*Engine power varies based on horizontal or vertical orientation, as well as by makes and models from each manufacturer.


Seal Repair Kit – Part #09220
38A 13156 O-Ring 3
38B 07721 O-Ring 3
39A 07723 Grooved Ring 3
41 13158 Support Ring 3
42 07711 V-Sleeve 6
Valve Assembly Kit – Part #09659
51 05594 Inlet Valve Assembly 1
56A 07658 O-Ring 1
56B 07635 Support Ring 1
Oil Seal Kit – Part #09221
32 07624 Radial Shaft Seal 3
33A 07627 O-Ring 3

Repair Kits Available

The repair kits listed to the right are available for this pump. If you need further information about these repair kits, or have questions about other specific parts for your pump, please contact you local Giant distributor or contact Giant customer service.

Service & Repair

Giant provides service on each pump and accessory that we sell. Many basic repair procedures are covered in the Giant repair manual. For all other questions on service or repair needs please contact your local Giant distributor.