Read the manual thoroughly and understand all of the instructions, cautions, and warnings before using this equipment. If any section of the manual is not understood, contact your nearest authorized dealer, or contact Generac Customer Service at 1-888-436-3722 (1-888-GENERAC), or www.generac.com with any questions or concerns. 

Troubleshooting water pressure issues with pressure washers

Pressure issues in pressure washers can stem from a variety of sources, from incorrect nozzle usage and blocked filters to inadequate water supply and equipment settings. By understanding the capabilities of your pressure washer and ensuring it is properly set up and maintained, you can effectively troubleshoot and resolve most issues. Also consider the appropriateness of the machine for your specific task and utilize specialized detergents to optimize cleaning and performance when applicable.

Environment

This article applies to all pressure washers.

Understanding your pressure washer’s capabilities

1. Pressure adjustment features

• Axial cam pumps: Note that axial cam pumps do not have a feature to adjust the pressure directly on the pump. Pressure changes are made through nozzle selection.
• Triplex pumps: These pumps feature an adjustable unloader valve which is factory set to achieve the highest pressure. Adjust the pressure control knob clockwise (+) to increase pressure and counterclockwise (−) to decrease pressure.

2. Evaluate the pressure washer’s suitability

• Before beginning your project, confirm that your pressure washer’s specifications meet the demands of the job. Some tasks might require higher pressure levels or specific features that your model may not provide.

3. Use of specialized detergents

• For tougher cleaning jobs, consider using detergents specifically designed for pressure washers and the surface you are cleaning. This can enhance cleaning effectiveness without solely relying on water pressure.

Common troubleshooting steps

1. Nozzle issues

Types of nozzles: Understand that different nozzles are designed for various cleaning tasks. Refer to the unit’s owner’s manual to verify the correct nozzle is being used. See What Do the Different Colored Nozzles Do on My Pressure Washer?

• Quick-connect nozzles are color-coded and have different spray angles, each suited for different applications. Choosing the correct nozzle is crucial for achieving the desired pressure and spray pattern.
• Adjustable nozzles come with an adjustable nozzle that allows altering the spray pattern by twisting it. Turn counterclockwise to concentrate the stream for higher pressure, or clockwise to widen the stream for lower pressure but larger coverage.

2. Maintenance

• Regularly inspect nozzles for blockages or debris, clean them using the provided tool, or replace them if necessary to maintain optimal performance.

3. Water supply and flow

• Verify that the spigot and any connected hoses are fully open and not restricted by kinks or leaks.
• Run water through the system for 30 seconds before connecting to the pressure washer to ensure a consistent flow and flush any possible debris from the hose.
• Inspect any parts of your water system for one-way valves, vacuum breakers, or check valves that could impede water flow.
• See What Precautions Should I Take when Connecting a Water Supply to my Pressure Washer? for more information on water supply requirements.

4. Purging air from the pump

• Remove any trapped air in the pressure washer by running water through it prior to starting. Trapped air can significantly reduce pressure to the pump. If the pressure appears to be fluctuating, there may be air trapped in the pump. To bleed the pump of any air:
  1. Turn the machine off and disconnect the supply hose (usually a garden hose).
  2. Trigger the gun on the power washer.
  3. With only the garden hose connected to the machine, turn on your water source and allow water to run through the pump of the machine for 20 to 30 seconds.
  4. Turn off the water, connect the high-pressure hose, trigger the gun, and try using the machine again.

5. Hose management

• Use a hose no longer than 50 feet to maintain adequate water pressure to the pump.
• Ensure the hose is free of kinks, obstructions, and leaks.
  • If the high-pressure hose shows signs of a leak, check the O-rings. If damaged, remove the old O-rings with a small flathead screwdriver and replace them with new ones.
  • O-ring replacement kits for pressure washers are available here.

6. Inlet water filter

• Check the pressure washer’s pump to see if the water inlet filter is blocked, clogged, or damaged. If the screen is damaged, remove and replace it. Clean regularly to prevent obstructions that can lower pressure and damage the pump.

7. Equipment settings

• Check all equipment settings, including the PowerDial™ or throttle settings, to ensure they are configured for the highest efficiency based on your cleaning needs.

8. Additional considerations

• Failed pressure sensor

The OneWash™ (discontinued) featured a low-water-pressure sensor. If the sensor detected low water pressure, then the machine would shut off. Current pressure washer models do not have this sensor.