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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; stainless plungers with hardened metal coating; nitrile seals with fabric reinforcing; stainless steel valves and machined stainless steel 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

Specification US Metric
Flow17.9 GPM67.7 L/min
Maximum Discharge Pressure5800 PSI400 bar
Crankshaft Speed750 RPM
Power71.6 HP53.4 KW
Max Temperature140 °F60 °C
Inlet Port Size(2) 1-1/4" BSP
Discharge Port Size(2) 3/4" BSP
Plunger Diameter1.1 in.28 mm
Stroke1.1 in.52 mm
Maximum Inlet Pressure145 PSI10 bar
Crankshaft Diameter48 mm
Crankshaft RotationTop of Pulley Towards Manifold
Key Width0.55 in.14 mm
Crankshaft MountingEither Side
Crankcase Oil Capacity1.6 gal 6.0 L
Weight375 lbs.170 kg
Volumetric Efficiency89%
Mechanical Efficiency83%
NPSHR83% Ft.-head

Horsepower Specifications

RPM GPM 3000 PSI 4000 PSI 5000 PSI 5800 PSI
300 7.2 14.9 19.9 24.8 28.8
400 9.5 19.7 26.2 32.8 38.0
550 13.1 27.1 36.1 45.2 52.4
600 14.3 29.6 39.4 49.3 57.2
650 15.5 32.1 42.8 53.4 62.0
700 16.7 34.6 46.1 57.6 66.8
750 17.9 37.0 49.4 61.7 71.6

Specification Images

Additional Drawings

  • GP7128 Exploded View
  • GP7128 Parts List
  • GP7128 Torque Specifications


  • Giant Industries Limited Warranty
  • GP7128 Installation Instructions
  • GP7128 Repair Instructions
  • Troubleshooting Guide


Sample Pump

Our Company

For 50 years, Giant Pumps has offered the most dependable positive displacement high-pressure triplex pumps available. Designed and built to the highest quality standards, customers count on Giant Pumps products to keep their equipment running. Every design detail of Giant Pumps products is optimized for long-life and reliable performance, making Giant Pumps the most trusted name in high-pressure pumps and systems.

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