Bleeding the air out of a pressure washer—or "priming" the pump—is a simple, crucial step to prevent pump damage and restore pressure. To do this without turning on the engine, attach your garden hose, turn on the water supply fully, and squeeze the spray gun trigger until water flows in a smooth, continuous stream.
Step-by-Step: How to Bleed Air from a Pressure Washer Hose
If the pressure washer is not new, turn off the pressure washer and disconnect the water supply hose. Hold the trigger on the spray gun or wand to release any remaining pressure in the system. Reconnect the water supply hose and turn on the water supply to purge any trapped air from the system.
Turn on the hose tap and run the water through the system for a minute or two. This will make sure that any air in the system is removed.
Do I need to bleed my pressure washer every time I use it? Yes. Bleeding before each use ensures trapped air is removed, which helps maintain consistent pressure and protects the pump from damage.
For most vehicles, a psi between 1200 and 2200 is recommended. This should give you enough cleaning power to blast away dirt and grime, but it's not so high that it could harm the paint or other delicate surfaces.
That suggestion of turning the water on and allowing it to run for a little will probably work if it's just air in the pipes. Allowing the water to run for a bit will push the air out of the pipes. If that doesn't work, either call the water authority or a plumber.
1,000 - 1,900 PSI: This PSI is on the low end, and is considered a residential unit. This type of pressure washer is good for the average homeowners to handle most household and automotive cleaning jobs, and is usually a hand carry electric model.
If you choose to use Dawn in your pressure washer, proper dilution is crucial. A general recommendation is to mix no more than a few ounces of Dawn with a gallon of water to prevent excessive foaming and reduce the risk of pump damage.
Pressure Tank
To function correctly, the tank is pre-filled with air, usually at a pressure 2 PSI below the point when the switch activates the pump. For a 40/60 setup, the tank should read 38 PSI when empty. Having this buffer of pressurized air reduces how often the pump needs to run, lowering wear and energy use.
Concrete surfaces, such as driveways, patios, and sidewalks, can accumulate tough stains and dirt over time. To clean them effectively, you'll need a pressure washer with a PSI range between 2,500 and 3,000. This level of pressure is powerful enough to remove embedded dirt, grime, and even mildew.
Keep The Pressure Low
Maintain an output pressure under 1,500 psi, which is enough to clear off stubborn dirt. Going any higher may damage your car's paint job—but not necessarily enough that you'll even notice right away. It's also possible to accidentally remove special detailing, such as ceramic coatings.
Manual and Machine Use: Suitable for use with professional sprayers, brushes, or pressure washers with downstream chemical injectors.
Never use a pressure washer on windows, roofs, or areas with lead paint, as it can cause breakage, water damage, or health hazards. Older bricks, awnings, and vehicles are too delicate for high-pressure spraying and should be cleaned with gentler methods.
If the pressure washer engine doesn't spin as you pull out the recoil starter rope, you probably need to replace the recoil starter, because it's not spinning the flywheel. If the starter rope won't budge when you try to pull it, the engine may be locked up or the recoil starter may have failed.
Our recommendation is to never idle your pressure washer for more than 60 seconds. If you can periodically cycle some fresh water through to keep it cool, you can extend this a bit, but in most cases, if you need to step away from cleaning, it's best practice to shut the pressure washer off.
Machine Shuts Down When Trigger is Released: When the unloader valve fails, the pump can't relieve pressure properly, causing the engine or motor to stall. Pressure Drops or Inconsistent Spray: If your pressure washer spray is weak or fluctuating, a stuck or worn-out unloader valve may be to blame.