A German-made triplex plunger positive displacement pump with reciprocating plungers for belt drive applications.

Aluminum 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; Teflon nitrile seals with EPDM O-Rings; stainless steel valves and forged brass 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 www.P65Warnings.ca.gov

  • CP425 Exploded View
  • CP425 Parts List
  • CP425 Torque Specifications
  • Giant Industries Limited Warranty
  • CP425 Installation Instructions
  • CP425 Repair Instructions
  • Troubleshooting Guide


U.S. Metric
Max Flow 5.5 GPM 21.0 L/min
Max Pressure 2030 PSI 140 bar
Max Speed 750 RPM
Max Temperature -40 ºF to 32 ºF -40 ºC to 0 ºC
Plunger Diameter 1.02″ 25 mm
Stroke 0.79″ 20 mm
Inlet Pressure 500 PSI 35 bar
Crankshaft Diameter 28 mm
Crankcase Oil Capacity 30 fl. oz. 1.0 L
Weight 38.3 lbs. 17.4 kg
Inlet Ports (2) 1″ BSP
Discharge Ports (2) 3/4″ BSP
Shaft Rotation Top of Pulley Towards Manifold
Shaft Mounting Either Side
Key Component Material
Manifold Forged Brass
Plungers Solid Ceramic Oxide
Valves High Grade Stainless Steel
Seals Teflon and Nitrile with EPDM O-Rings
Gear End Aluminum

Click the image to enlarge


RPM GPM 500 PSI 1000 PSI 1500 PSI 2030 PSI
350 2.59 0.9 1.8 2.7 3.6
450 3.33 1.1 2.3 3.4 4.7
550 4.07 1.4 2.8 4.2 5.7
650 4.81 1.7 3.3 5.0 6.7
750 5.55 1.9 3.8 5.7 7.8

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.


Plunger Packing Kit – Part #CP09595
21 CP07266-0003 O-Ring, EPDM 3
22 CP08059 O-Ring 3
23 CP06144 Grooved Seal, Brown 3
23B CP12255-0020 Grooved Seal, Teflon 3
24 CP08376 Pressure Ring 6
Valve Assembly Kit – Part #CP09596
27A CP04643 Valve Assembly 6
33 CP07214-0003 O-Ring, EPDM 6
Oil Seal Kit – Part #CP09641
19 CP05444 Oil Seal 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.