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Pressure washer is surging/pulsing: An in-depth comprehensive guide

2023-11-03

Pressure washer, a powerful tool that has become a staple in home maintenance and professional cleaning services, can sometimes act up with issues like surging or pulsing. This phenomenon disrupts the steady flow of water, leading to inefficient cleaning and potentially damaging surfaces. This comprehensive guide will help you understand pressure washer surging/pulsing, including the issue, its causes, how to diagnose it, and ultimately, how to fix it.

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Understanding what pressure washer surging/pulsing means

Surging or pulsing in the context of pressure washers refers to an inconsistent flow of water. Instead of a steady, powerful stream of water, the pressure fluctuates, causing the water to come out in bursts or pulses. This irregularity not only affects the cleaning efficiency but can also lead to wear and tear of the machine components if left unchecked. Plus, the inconsistent pressure can make cleaning tasks more time-consuming and may even compromise the quality of your work.

Common causes of pressure washer surging/pulsing

Pressure washer surges or pulses can be caused by various issues. Here's a list of common causes:

  • Kinks and blockages: These can restrict the flow of water, resulting in inconsistent pressure.

  • Plugged nozzle: Over time, debris can build up inside the nozzle, causing it to become plugged and disrupt the water pressure.

  • Dirty inlet or discharge valve: If these valves are dirty, they may not open and close properly, leading to irregular water pressure.

  • Faulty pressure regulator: The regulator controls the water pressure. If it's damaged or malfunctioning, it could cause the pressure to fluctuate.

  • Worn pump seals: These seals prevent water from leaking out of the pump. If they're worn or damaged, they might allow air to enter the pump, causing pulsations.

  • air in the pump: This can create inconsistent pressure as the pump struggles to push out both air and water.

Solutions and fixes for surging/pulsing in pressure washers

Generally, the first step in troubleshooting a surging pressure washer is to check the spray nozzle for dirt. Check the unloader valve for damage or trapped air to see if the nozzle is okay. Check the hose and filter for any leaks or restrictions. If there are none, check your pressure washer's water supply and valves.

Safety is paramount during this process. Always ensure the pressure washer is turned off and disconnected from the power source before you start inspecting it.

Check the nozzle

Most of the time, the pressure washer's nozzle is the main problem behind the pressure build-up. Check the nozzle of your pressure washer. Mount a different one and see if that fixes the problem. If so, the nozzle is likely dirty.

If dirt is inside, clean it with a thin metal wire or use a nozzle cleaning kit. If your nozzle is worn out, you need to replace the nozzle.

Check the unloader valve

The second step is to check the unloader valve. It diverts the water flow from the pump to the bypass. This unloader can also relieve the pressure build-up of water from a pressure washer's nozzle.

The unloader is located above the water inlet. Locate the unloader and open it to check if it is blocked or worn out. You can adjust the unloader valve slightly to increase washer pressure. Connect a pressure gauge when adjusting the unloader valve to prevent the pressure from becoming too high.

During unloader valve adjustment, check the pressure and find the best setting. The spike you will see when releasing the trigger should not exceed 10%. High spikes can damage the internal parts of the pressure washer.

After adjusting the unloader valve, if your machine is still producing low pressure, your valve may be damaged and have to be replaced.

Check the hose and filter

Check the inlet hose and filter for any restrictions causing low pressure. In this case, clean the hose thoroughly. Make sure the faucet you use is fully open.

It is also possible that there is air trapped in the pressure washer or hose. Disconnect the hose from the pressure washer. Let the water flow until only water comes out. Reconnect the hose to the pressure washer. Now, pull the trigger and let the water flow for some time. This should remove any air from the system.

Test the water supply

Sometimes, the source may not supply enough water to your pressure washer. This can result in cavitation or air bubbles forming in the nozzle. Cavitation is a clear sign that insufficient water is reaching the pressure washer.

Most manufacturers state that they require 2 gallons per minute (GPM). But our experience is that with less money, they still work fine. But make sure you have a flow of at least 0.9 GPM. We recommend using a suitable hose. The minimum diameter should be ¾ inch to avoid any build-up in your pressure washer. The longer the hose, the more critical a proper hose is.

Assume that the water supply is fine. Check the pump packing. If they are worn out, replace them.

Check the pressure washer valves

The final step in troubleshooting a pulsing pressure washer is to check the valves. If the inlet or discharge valves are not working well, they must be replaced. The inlet valve lets water into the manifold. The plunger pushes water toward the discharge valve as the inlet valve closes.

The discharge valve releases the water. It is located on the outside of the pump. If your valves are in good working order, check the valve spring. It may break. In this case, change it.

Look for air in the pump

Signs of air in the pump could include unusual noises or vibrations from the machine. To remove trapped air, switch on the pressure washer without the cleaning wand attached and let the water run for about 5-10 minutes. This procedure should push out any trapped air.

Preventative measures to avoid pressure washer surging/pulsing

Preventing surging or pulsing in pressure washers involves regular maintenance. Even if you've never serviced a pressure washer before, the following paragraphs will tell you everything you need to know about regular pressure washer maintenance.

Before using

  • On gasoline-powered versions, check the oil and fuel levels. 

  • Check your pressure washer's wand extension to ensure it's not blocked.

  • Check the trigger and lock of the spray gun. Replace the spray gun if it is not working correctly.

  • Check for cuts, bulges, leaks, or other damage at the high-pressure line and the hose connections. If the hose is damaged, read the manufacturer's replacement instructions.

  • Check your water source to ensure it provides a consistent supply at the required GPM.

  • Regularly inspect the unloader valve for wear and tear, and ensure it's adjusted correctly.

  • Before starting your pressure washer, make sure there's no air in the pump. You can do this by running water through the machine without the cleaning wand attached.

After using

  • Allow the pressure washer to cool by locking the trigger. Disconnect the high-pressure spray gun, garden hose,  and wand extension.

  • Drain the pump of any remaining water. Pull the recoil handle about six times if you're using a gas-powered model. If you have an electric type, turn it on until the pump begins to pump water, then quickly turn it off.

Conclusion

Understanding the causes and solutions for a surging or pulsing pressure washer is crucial to maintaining the efficiency and longevity of your equipment. Regular checks and maintenance can prevent these issues, ensuring your pressure washer continues to perform optimally. With this guide, you can take the right steps towards diagnosing and fixing any surging or pulsing problems, ensuring your pressure washer serves you effectively for years to come.

Learn more about pressure washer troubleshooting:


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