Pressure Washing Pump Types

The are two general groups of positive displacement pumps:

• Reciprocating – Uses pistons, plungers or diaphragms.

• Rotary – Uses screws, gears, vanes or lobes.

All pressure washer pumps are in the reciprocating group and use pistons or plungers to add energy to the water. There are two main differences between the piston and plunger pump.

1. The piston pump has the cylinder seal attached to the piston so it moves with it on each stroke. The plunger pump has the cylinder seal at a stationary point that the piston moves through with each stroke.

2. The piston pump is driven by a drive shaft attached to the swash plate or wobble plate. The plunger pump is driven by a crankshaft.

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How To Buy Replacement Pump and Parts

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The description of the pump will often tell all you need to know about if the pump can work with your pressure washer. However, be sure that the drive shaft measurements match… And that the engine/motor has enough power for the pump. Also be sure it is the correct configuration – vertical or horizontal – for mounting.