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What are the differences between plunger pumps and piston pumps?

Piston Pump vs Plunger Pump Chart

How your pressure washer operates depends on the type of pump it uses. There are two main types of pressure washer pumps: plunger pumps and piston pumps. Knowing the similarities and differences between the two can help you better decide which pressure washer model is right for you.

Similarities between plunger pumps and piston pumps

Plunger pumps and piston pumps operate in much the same way. They’re both reciprocating displacement pumps that pull water through a one-way intake valve, pressurize it and discharge it through a one-way outtake valve.

Most pressure washer models have two (duplex) or three (triplex) pistons or plungers. Duplex pumps need to work harder and faster to produce the same amount of flow rate as triplex pumps. Consequently, duplex pumps tend to wear out more quickly.

How piston pumps work

A piston pump consists of a reciprocating piston that fits tightly inside a cylinder with a seal. The piston is attached to a rotor that forces it to travel up and down the cylinder. As the piston reciprocates up and out, it sucks water into the cylinder through the intake valve. When the piston is pushed back through the cylinder, it pushes water through the outtake valve.

The pistons are connected to seals which move in unison with the pistons. For this reason, piston pumps tend to wear out quickly and can’t produce high amounts of pressure. Therefore, piston pump pressure washers are most suitable for residential use for washing vehicles, fences and siding.

How plunger pumps work

Unlike a piston that fits tightly inside the cylinder, a plunger fits loosely. The plunger creates negative and positive water pressure inside the cylinder as it moves up and down. It sucks water through the intake valve and sends it out the outtake valve.

The seal is stationary, which allows plunger pumps to produce higher pressure than piston pumps. Plunger pumps are well-suited to high-pressure industrial applications, such as removing graffiti and cleaning or washing down heavy-duty industrial vehicles.

Pressure washers in Western Canada and North Dakota

Whether you need an in-plant pressure washer or mobile washing system, Hotsy Water Blast has what you need. All our units are CSA safety certified and backed by a seven-year pump warranty. We also provide scheduled maintenance services and a comprehensive selection of pressure washer parts and accessories. Contact Hotsy’s design and engineering services to request a free estimate on your custom pressure washer today.