How to Get Air Out of a Pressure Washer: Step-by-Step Guide
Step-by-step instructions to remove air from a pressure washer pump, prevent sputtering, protect seals, and maintain reliable spray performance long-term.
Bleeding air from your pressure washer is the first step toward restoring a steady, spray pattern. Start by turning off and unplugging the unit, then relieve any stored pressure. Locate the bleed valve on the pump, open it slowly, and run water through until a continuous, air-free stream flows from the nozzle.
Why air in a pressure washer causes problems
Air in a pressure washer disrupts the water path, causing sputtering, reduced nozzle pressure, and an uneven spray pattern. If air is not removed, it can accelerate seal wear and shorten pump life. Pressure Wash Lab notes that mastering the bleed is a foundational skill for homeowners and pros. In this section, you’ll see how air behaves inside the system and why a proper bleed matters before you perform bigger repairs. You’ll map the flow: water source → inlet hose → pump → high-pressure hose → nozzle. Knowing where air hides (tight fittings, loose hose clamps, or a partially opened valve) helps you approach the bleed with confidence.
Common causes of air lock in pressure washers
Air locks aren’t a single problem; they arise from several points in the plumbing and pump. Leaky or loose inlet hoses can draw air from the reservoir, while cracked fittings or missing O-rings invite air pockets. If you skip priming the suction line after replacing hoses, air can be drawn into the pump. Running the unit without water or with the water source blocked can trap air at the pump head. Finally, some unloader valves or relief valves are set to release pressure too early, which can allow air to re-enter the system after bleeding. Understanding these causes helps you diagnose the root issue rather than just treating symptoms.
How to diagnose an air lock: quick checks
Begin with simple, safe checks: ensure the machine is off and unplugged, the trigger is released, and the hoses are connected correctly. Listen for sputtering or coughing from the nozzle, a telltale sign of air pockets. Check the water supply to confirm constant flow and inspect fittings for visible leaks. If the spray resumes after bleeding but returns later, re-check the inlet hose and unloader. The quickest diagnostic is observing the discharge: steady water without air means the bleed succeeded; intermittent spray hints at a seal or hose leak elsewhere in the system.
Bleeding air: a practical, stepwise overview
Bleeding air is a repeatable, low-risk task when done with the engine off and pressure relieved. Start by turning off the unit and releasing any stored pressure. Then locate the bleed valve or port on the pump. Open the valve slowly while holding the spray wand away from people and surfaces. As water begins to flow out, close the valve gradually only when a continuous stream replaces the air bubbles. Finally, test the nozzle with the trigger pulled, permitting a brief flow to purge any residual air. If you can’t locate a bleed valve, consult the manual or contact the manufacturer for the exact location since designs vary by model.
Maintenance to prevent future air locks
Prevention is better than bleeding. Keep the inlet hose and fittings tight and free of kinks, replace worn O-rings, and ensure water supply is clean and continuous. Use the appropriate nozzle and avoid running the pump dry. Regularly flush the system after heavy cleaning and inspect the unloader valve for proper operation. Clean or replace filters to avoid debris that can trap air as the pump seals guide water. By building a small routine—check fittings, purge to remove air, and test spray—you reduce the odds of recurring air pockets.
Safety considerations and common mistakes
High-pressure water can cause injury, so wear eye protection and gloves whenever you work near the wand or fittings. Never loosen bleeding components while the unit is pressurized or while it’s running. Avoid forcing a valve or valve stem; if it won’t move easily, stop and recheck alignment and torque. Keep hands away from the spray stream, and never point the nozzle at yourself or others, even during bleed tests. A common mistake is bleeding with the nozzle still attached and the trigger pulled; always relieve pressure first and perform the bleed with the wand pointed away from people and delicate surfaces.
Model-specific notes: pump types and bleed fittings
Different pump types use different bleed fittings. Axial cam pumps often have a dedicated bleed screw on the side; triplex plunger pumps may require loosening a bleed cap or valve. Some models use a small chamber valve you depress with a screwdriver; others rely on the operator manually lifting a bleed lever. If you’re unsure, locate the pump body label and look for a bleed instruction diagram. The key is to identify the bleed port, work slowly, and avoid overtightening seals.
Troubleshooting flow: what to do if air returns
If air reappears after you’ve bled the system, systematically re-check common culprits. Re-inspect all hose connections for tightness and seals for wear; replace worn o-rings and gaskets as needed. Re-bleed the pump, ensuring you follow the exact valve sequence for your model. Check the water source for adequate flow and suspect hidden leaks in the inlet line. If the problem persists, consider professional service or consult the user manual for model-specific bleed procedures.
Quick-start checklist for a ready-to-use setup
- Confirm power supply and outlet are correct and secure.
- Ensure the water source provides a steady flow and is connected.
- Identify the bleed valve location and have a screwdriver handy.
- Bleed the system until water runs clean and air-free.
- Reconnect the nozzle, test spray at low pressure, and increase gradually.
- Inspect hoses and seals for leaks and tighten as needed.
- Clean the filter and run a short burst to confirm steady performance.
Tools & Materials
- Pressure washer owner's manual(Model-specific bleed procedures vary; consult the official guide for exact location.)
- Flathead screwdriver(Needed to operate bleed valve screws on many pumps.)
- Adjustable wrench(Used to loosen fittings if needed; avoid overtightening.)
- Pliers(Helpful for removing clamps or securing hoses during bleed.)
- Garden hose or water source(A steady water supply is essential to purge air and prime the line.)
- Drain pan or absorbent towels(Catches water and prevents spills during bleeding.)
- Safety gloves(Extra protection when handling fittings and hot surfaces.)
Steps
Estimated time: 10-15 minutes
- 1
Power down and relieve pressure
Turn off the unit, unplug the power cord, and squeeze the trigger on the wand to release any built-up pressure. This prevents unexpected spray and reduces the risk of hose whip during the bleed.
Tip: Always start with safety—protect eyes and hands before touching the machine. - 2
Locate the bleed valve or port
Find the bleed valve on the pump body or the designated bleed port. If you can’t locate it, refer to the owner’s manual or search for your model’s bleed instructions online.
Tip: If you’re unsure, don’t force the valve; consult the manual to avoid damage. - 3
Connect water source and purge line
Attach the garden hose to the inlet and ensure a steady water flow. Open the inlet valve slowly to prime the suction line and push any trapped air toward the bleed valve.
Tip: Keep the wand pointed away from people while purging to avoid splashes. - 4
Open the bleed valve gradually
With the unit still off, slowly open the bleed valve and observe for air escaping with water. Close the valve once a continuous water stream replaces the air bubbles.
Tip: Work slowly—rapid valve movements can flood the system and miss air pockets. - 5
Test the spray
Attach the nozzle, engage the trigger, and run a short test spray. If air persists, repeat the bleed process and recheck all connections.
Tip: If you hear sputtering again, re-check the inlet hose for leaks. - 6
Verify and finalize
Ensure there is a steady, air-free water flow, then tighten any fittings, store tools, and clean the area. Document any worn seals for replacement later to prevent future air ingress.
Tip: Document the bleed steps for your future maintenance routine.
Quick Answers
Why is there air in my pressure washer?
Air pockets usually come from loose fittings, dry priming, or leaks in hoses. Bleeding helps restore consistent pressure and spray. Regular checks help prevent re-entry of air.
Air pockets typically come from loose fittings, dry priming, or leaks. Bleeding improves spray consistency and protects the pump; check fittings and hoses if air returns.
Can I run the pressure washer with air in the system?
No. Running with air can cause uneven pressure and may wear seals faster. Bleed the system first and verify a continuous water stream.
No—running with air can damage seals and reduce performance. Bleed the system and ensure a steady water flow before use.
Do all models have a bleed valve?
Most do, but locations vary by model. If you can’t locate it, consult the manual or manufacturer support for the exact bleed procedure.
Most models have a bleed port, but its location varies. Check the manual or contact support to find the right bleed procedure for your unit.
What if air returns after I’ve bled the system?
Re-check all hose connections and seals for wear. Re-bleed following the model’s sequence, and inspect the unloader valve for proper operation.
If air comes back, re-check hoses and seals, then re-bleed following your model’s steps and check the unloader valve.
How often should I bleed air?
Only when you notice symptoms like sputtering or intermittent spray. Routine bleeding isn’t typically required unless you service the pump or replace components.
Bleed only when you notice symptoms. Routine bleeding isn’t usually necessary unless you’re servicing the pump.
Is bleeding air safe?
Yes, when done with the unit off, unplugged, and pointed away from people. Use protective gear and follow the manufacturer’s guidance.
Yes, it’s safe if you power down, unplug, and point away from people while bleeding.
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Key Takeaways
- Bleed air first to restore steady spray
- Relieve pressure before any bleed procedure
- Check for leaks and worn seals after bleeding
- Consult the manual for model-specific bleed steps
- Regular maintenance reduces future air pockets
