A German-made reciprocating triplex plunger pump.

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; nitrile seals (with fabric reinforcing); stainless steel valves; and forged brass manifold.

Gearbox and bell housings (to connect to gasoline, diesel, electric or hydraulic drive) and pulsator valve.

  • P425HP Exploded View
  • P425HP Parts List
  • Giant Industries Limited Warranty
  • P425HP Installation Instructions
  • P425HP Repair Instructions
  • Troubleshooting Guide


U.S. Metric
Flow 10.7 GPM 40.6 L/min
Max Discharge Pressure 3045 PSI 210 bar
Max Inlet Pressure 145 PSI 10 bar
Plunger Diameter 0.98″ 25 mm
Stroke 0.79″ 20 mm
Max Temp 158 °F 70 ºC
Crankshaft Diameter 1.10″ 28 mm
Key Width 0.32″ 8 mm
Weight 42 lbs. 19 kg
Crankcase Capacity 30.4 fl. oz. 0.9 L
Inlet Ports (1) 1″ BSP, (2) 3/4″ 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 Nitrile With Fabric Reinforcing
Gear End Aluminum

Click the image to enlarge

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.