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Pressure Washer Pump Types and What They Do

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Make the most of your prized pressure washer. 

If you have a pressure washer, you need a pressure washer pump. There are three main types on the market: wobble pump, triplex pump, and axial cam pumps.

We’ll walk you through these pressure washer pump types, calling out what makes them unique as well as the main pros and cons.

By the end, you’ll be familiar with the different types and what they have to offer.

Pressure Washer Pump Types

The wobble pump has a PSI of below 2500, is 70 percent efficient, and lasts around three years. The axial cam pump is more efficient, has a PSI below 3500, and lasts around five to eight years. Finally, the triplex pump is around 90 percent efficient, lasts up to 10 years and has a PSI of at least 3000.


Are Pressure Washer Pumps Universal?

No — they are not. Some state that they’re universal, but the reality is that they only work with the majority.

You should always check the dimensions of the pump against your pressure washer to make sure they’re compatible. You must also check the PSI and GPM as matching up varying specs will give you poor results.

Types of Pressure Washer Pumps

There are three main types of pressure washer pumps: wobble pumps, triplex pumps, and axial cam pumps. We’ll walk you through what each one is, the pros and cons, and a handy chart with additional specs.

Wobble Pump

A wobble pump is an entry-level option that uses a wobble plate. The wobble plate is connected to a drive shaft to push pistons back and forth. This creates suction to push the water out with great force. However, the pump is only around 70 percent efficient since it has to push the water and the springs.

Normally, these pumps are sealed shut when they leave the factory due to their intricate parts. This also makes them not widely available for repair since they have small parts in tough-to-reach places.

Similar to axial cam pumps, they have a lifespan of around two to three years if used around three hours a week.

Pros

  • They can run dry.
  • They use high pressure and push out water with a lot of force.
  • They can prime themselves.
  • No seals to move back and forward.

Cons

  • Only about 70 percent efficient.
  • They can’t be repaired.
  • Low water flow.

Additional Specs

Maximum Pressure (PSI) Below 2500
Maximum Flow Rate (GPM) Below 2.0
Pump Efficiency 70 percent
Compatible Pressure Washer Type Low flow electric pressure washers
Lifespan 2-3 years when used 3 hours per week

Triplex Pump

Product Image of the AAA Pumps 90037 Horizontal Triplex Plunger Replacement Pressure Washer Pump Kit, 3700 PSI, 2.5 GPM, 3/4' Shaft, Includes Hardware and Siphon Tube, for Industrial Gas Powered Machines, Green

These are designed for professional-level pumps. They emit super high pressure and last for thousands of hours between maintenance or need for repairs.

Triplex pumps are similar to a car engine in that they have a crankshaft and connecting rods to drive position action pistons. These suck in and push out water with each stroke.

These are nearly 90 percent efficient, so they’re very high quality. They run cooler, since they use less RPM than the engine, so they are more eco-friendly and cost-effective.

In a triplex plunger pump, the pistons stroke 120 degrees apart which offers smoother flow over the revolution of the crankshaft.

When you do need to make repairs, it’s easy since the replacement valves are easily accessible. Overall, these have around a 10-year lifespan.

Pros

  • Nearly 90 percent efficient.
  • They have a long lifespan.
  • They use high water pressure.
  • Less prone to leaks.
  • The seals are stationary.

Cons

  • They are more expensive.

Additional Specs

Maximum Pressure (PSI) 3000 and above
Maximum Flow Rate (GPM) 3.0
Pump Efficiency 90 percent
Compatible Pressure Washer Type Professional level washers
Lifespan Around 10 years

Axial Cam Pumps

Product Image of the OEM Technologies 90029 Replacement Pressure Washer Pump Kit, 3400 PSI, 2.5 GPM, 3/4' Shaft, Includes Hardware and Siphon Tube, for Residential and Industrial Gas Powered Machines

These are also known as swash plate pump. They are intermediate-level pumps, so they’re slightly better than the wobble pump but not as powerful as the triplex pump.

This kind of pump has a higher PSI and GPM than a wobble pump. It’s similar in design but slightly different due to the pistons that rotate around the swashplate.

The swashplate is at an angle that allows the pistons to stroke it as they move from one side to pull up water, and then the other side to push out the water. It also rotates on the same axis as the driveshaft, since these two pieces are connected.

This allows for larger oil reservoirs and bearings which increases the lifespan of the pump.

Pros

  • Lightweight and compact.
  • Self-priming.
  • More efficient than wobble pumps.
  • You can adjust the flow of water manually.
  • Longer lifespan than wobble pumps.

Cons

  • They get hot and take a while to cool down.
  • You may experience excess vibration.

Additional Specs

Maximum Pressure (PSI) Less than 3500
Maximum Flow Rate (GPM) 2.5
Pump Efficiency Between 70 and 90 percent
Compatible Pressure Washer Type Gas pressure washers below 3500 PSI
Lifespan 5-8 years when used 3 hours per week

Pressure Washer Pump FAQs

Can I Put a Bigger Pump on My Pressure Washer?

You should go for a pump that is intended to fit the size of your pressure washer. If in doubt, you can maybe get away with going for a slightly bigger size, but check with the manufacturer of the pump and test it if able.

How Do I Know If My Pressure Washer Pump Is Bad?

Here are a few signs that indicate if your pump is bad:

  • Read your pressure gauge: If you have a pressure gauge, read the results. The line should be maintained when there’s pressure. If the line isn’t moving at all, or is low, or is flicking around a lot, your pump is bad.
  • Lack of power: If your pressure washer isn’t reaching the advertised PSI, the pump could be bad.
  • Bad water flow: If the pressure washer isn’t reaching the advertised GPM, this could also indicate the pump is bad.
  • Dirt and buildup: If you notice dirt and build up at the pump, at the connections, or in the pressure washer, then your pump is bad and needs to be deeply cleaned. You should maintain your pump rather than letting dirt build up.
  • Mini explosions: Not like a spark, but an explosion of air can indicate air is stuck in the pump.
  • General performance problems: Other performance problems such as poor power, inconsistent results and low pressure could indicate that you didn’t choose the right pump for your pressure washer.
  • Leaks: If you’re experiencing leaks, there could be an issue with the pump.
  • Physical flaws: Another main sign that something is wrong with your pump is if you notice physical flaws and damage.

Can You Repair a Pressure Washer Pump?

You can repair triplex pumps easily, but axial cam pumps and wobble pumps are harder to fix. In fact, wobble pumps are pretty much impossible to fix.

According To The Experts

While it may be tempting to attempt to fix your pump, sometimes replacement is the best way forward. Contact a professional and get their opinion on it first.

Do You Need a Water Pump for a Pressure Washer?

Yes — this is what causes the pressure washer to run. It sucks in water from your home’s water supply and pushes it through the pressure washer. Without it, your pressure washer wouldn’t work.


Pump, Pressure and Pristine Pavements

With the right pressure washer pump type for your pressure washer, your machine will be working better than ever. You’ll have those pristine pavements, driveways, and other surfaces.

The main types are wobble pumps, triplex pumps, and axial cam pumps. Triplex pumps are the most powerful, so you may be leaning towards that. But you have to keep in mind that you can only choose the one that’s compatible with your pressure washer.

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About the Author

Beth McCallum

Beth McCallum is a 20-something freelance writer & book blogger with a degree in creative writing, journalism and English literature. Beth firmly believes that a tidy house is a tidy mind. She is always looking for new ways to sustainably clean and tidy her house, that's kind on the environment but effective in the house, too!

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