Pressure Washer Repair Problems and How to Fix Them

man using a pressure washer to clean a deck

Pressure washers are powerful cleaning tools that can tackle even the toughest outdoor grime and dirt. However, like any mechanical device, pressure washers can develop issues that prevent them from working properly. Knowing the most common pressure washer problems and how to fix them will allow you to troubleshoot problems quickly and get your washer back up and running.

Low Pressure

Low pressure is one of the most common problems with pressure washers. There are a few potential causes of low pressure:

Incorrect nozzle size – Using the wrong size nozzle can restrict water flow and reduce pressure. Make sure you are using the nozzle size recommended by the manufacturer.
Worn nozzle – Over time, nozzles wear out and the hole where water exits enlarges. This allows more water through but at lower pressure. Replace worn nozzles.
Clogged nozzle – Debris blocking the nozzle hole reduces pressure. Carefully clean nozzles to remove any obstructions.
Insufficient water supply – Pressure washers need a high volume of water to generate pressure. Make sure your hose can supply at least 5 gallons per minute.
Worn pump components – Internal pump parts like valves, seals, and cylinders eventually wear out, reducing pressure they generate. You may need to have your pump repaired or replaced.

Follow these troubleshooting steps for low pressure:

Remove lance and trigger gun and turn on pressure washer. If pressure coming directly out of pump is low, your issue is likely internal – continue troubleshooting. If pressure is normal without lance/trigger, issue is with accessories.
Check nozzle size and replace if incorrect or worn.
Verify adequate water supply through hose using a 5 gallon bucket and stopwatch to time how long it takes to fill.
Have authorized service center evaluate pump and internal components. Repair or replace parts as needed.

Taking the time to properly diagnose low pressure will get your pressure washer blasting at full power again.

Leaking

It’s not unusual for pressure washers to leak a little bit of water when in use. However, excessive leaking can be caused by:

Worn plunger seals – These seals inside the pump prevent water from flowing backward. If they leak, pressure drops and water oozes out around the pump.
Damaged o-rings/gaskets – There are o-ring type gaskets throughout a pressure washer to seal components like hose connections. If they get cracked or worn, high pressure water leaks out.
Loose fittings/connections – Vibration can cause fittings screwed into pump heads and hose connections to loosen over time, opening gaps for water to leak through.

Follow these troubleshooting tips for leaking pressure washers:

Turn off and disconnect power and water supply lines. Relieve any residual pressure.
Check all fittings and connections. Tighten any loose fittings with appropriate sized wrenches. Apply thread seal tape if necessary.
Inspect o-rings and gaskets. Replace any that are cracked, damaged, or worn out.
Have authorized service center evaluate internal seals and plungers. Replace any worn parts that cause leaking.

Catching leaks early and replacing worn seals/gaskets is crucial to prevent leaking from damaging internal pump components. Always use manufacturer recommended replacement parts.

No Pressure

It can be incredibly frustrating when you pull the trigger on your pressure washer and no water comes out at all. Some of the most common causes of a pressure washer not producing any pressure include:

Pump inlet valve failure – This one-way valve allows water into the pump but closes to enable pressurization. If stuck open, water flows through pump with no pressurization.
Unloader valve failure – This regulates pressure coming out of the pump. If stuck open, all pump pressure gets released back to the inlet side.
Inlet filter clogged – Filters on inlet lines prevent debris from entering the pump. If extremely clogged, not enough water can enter pump to pressurize.
Worn check valve – Check valves prevent backflow after pressurization. If worn out, water flows backward instead of exiting lance.

Follow these tips to troubleshoot no pressure:

Verify adequate inlet water supply. Disconnect inlet line before pump and observe flow.
Clean or replace inlet filter if very clogged.
Have authorized service center test unloader and check valves. Replace any faulty parts.
Evaluate inlet/outlet valves for proper sealing and operation. Repair or replace as needed.

Careful diagnosis is key to figuring out why a pressure washer has completely lost pressure generating capabilities. Often it takes a trained professional to evaluate faulty valves and components.

Rough Running

Pressure washers that sputter, surge, or simply feel rough and erratic when running often have one of these underlying problems:

Inadequate water supply – Running low on inlet water causes pump to sputter each time it runs out of available water. Confirm adequate water volume.
Hot inlet water – If inlet water source becomes heated by the sun or environment, it can form bubbles in the pump causing uneven flow. Check water temp before inlet.
Dirty water filter – Debris clogging the water filter causes uneven flow issues. Remove and clean filter regularly.
Dirty air filter – Oil bath air filters can get contaminated affecting airflow to pump. Replace air filters when dirty.
Failing pressure switch – This switch engages and disengages to regulate optimal pressure levels. If failing, it causes uneven pressure. Have tested at service center.

Follow these troubleshooting steps for rough running pressure washers:

Verify adequate inlet water volume using 5 gallon bucket test at faucet/hose supplying the pressure washer.
Check inlet water temperature. Move to cooler water source if warmer than 80°F.
Remove and clean water and air filters. Replace if unable to fully clean debris buildup off filters.
Have authorized service center test pressure switch cut-in/cut-out pressures for proper operation. Replace if faulty.

Running smoothly is crucial to pressure washer performance and pump/motor lifespan. Identify and address the underlying cause of rough operation as soon as it starts.

Pulsating

Pressure washers should spray a steady, even stream of water. If you notice yours pulsating, try these troubleshooting tips:

Clogged nozzle – Partially blockages in the nozzle can obstruct water flow, causing pulsating as pressure builds up and is released. Remove debris or replace nozzle.
Pump inlet/outlet valves failing – Worn valves allow pressure to leak back unevenly. Have valves inspected and repaired by authorized service center.
Loose drive belt – Pump drive belts can slip when loose or worn, causing intermittent pressurization. Tighten/replace per manufacturer instructions.
Worn circulation valve – This valve recirculates water when trigger isn’t pressed. If worn out, it causes uneven flow and pressure. Replace faulty valves.
Clogged discharge hose – Buildup inside discharge hose causes back pressure to vary, resulting in pulsating output. Clear obstructions in hose.

To troubleshoot and fix pulsating:

Remove and thoroughly clean nozzle to remove any debris clogging it. Replace if worn out.
Have authorized service center fully evaluate inlet/outlet valves and circulation valve operation. Repair or replace faulty valves.
Check drive belt tension. Tighten/replace per manufacturer specs if loose.
Remove discharge hose and clear any stuck debris that could be clogging hose.

Addressing pulsating issues promptly will improve cleaning performance and prevent additional pump damage from pressure fluctuations.

Overheating

Excessive heat is never good for the inner workings of pressure washers. Overheating can be caused by:

Insufficient water supply – Without enough inlet water flow, pumps overheat quickly from friction and moving components. Verify adequate water volume.
Blocked water inlet – Severe clogs or kinks in the inlet line restrict water supply, leading to overheating. Check for obstructions.
Using hot water – Drawing inlet water from a hot source raises temperatures for pump components. Use only cold water under 80°F.
Exceeding duty cycle – Using a pressure washer beyond the recommended duty cycle duration will overtax the motor. Allow appropriate rest periods.
Incorrect pressure settings – Adjustable unloader valves set too high overwork pump and lead to overheating. Use pressures per manufacturer recommendations.
Damaged/worn motor parts – Issues with bearings, rotor, stator windings and more can generate excess heat from friction. May require professional service.

Here are some steps to prevent overheating problems:

Check inlet water flow using 5 gallon bucket and stopwatch, minimum 5 GPM. Resolve any supply issues. Use larger diameter hose if necessary.
Inspect inlet hose/filter for kinks and clogs. Fix any obstructions restricting water flow.
Confirm inlet water temperature is cool, not warm water heated from external sources.
Adhere to recommended duty cycle limits before allowing machine to rest and cool down.
Adjust pressures to align with manufacturer specs for specific nozzles. Do not overpressure.
Schedule preventative maintenance checks to identify worn parts before failure.

Closely monitoring duty time, water supply, pressure settings and more will optimize operating conditions and prevent overheating failures. Catch problems early and have unit serviced promptly as needed.

Preventing Pressure Washer Problems

While even well-maintained pressure washers are bound to encounter problems eventually, you can take these proactive maintenance steps to reduce issues and prolong your machine’s lifespan:

Follow run time limits – Adhere to manufacturer duty cycle recommendations to prevent overtaxing motors. Allow units to fully cool before resuming operation.
Use pump protector fluid – Adding specialty anti-freeze fluids prevents internal corrosion and wear during storage periods.
Detach hoses & guns when storing – Removing accessories reduces tension on components and prevents premature wear of o-rings and seals from distortion.
Clean water inlet filter – Debris trapped in this filter reduces water supply volume leading to overheating, low pressure and more. Rinse regularly.
Protect from freezing – Freezing temperatures can damage pumps, hoses, and other components. Store in above freezing environments.
Inspect/replace worn parts – Check drive belts, fittings, valves and seals for wear regularly. Schedule full maintenance annually.

Investing a little time in preventative steps goes a long way towards avoiding bigger repair headaches down the road! Address any problems promptly to minimize cost and downtime.

When to Call a Professional

While proactive maintenance keeps many minor issues at bay, most pressure washers will eventually need professional service. Seek help from an authorized service center for:

Pump repairs – Only trained technicians have the expertise to safely disassemble pumps, properly evaluate internal wear, and rebuild or replace components.
Electrical issues – From motors to circuit boards, specialized knowledge is required to test electrical parts and determine necessary repairs.
Corrosion/scale cleaning – Over time mineral deposits accumulate inside components, requiring chemical cleaning. Improper techniques can damage parts.
Intermittent problems – Complex problems that are difficult to consistently reproduce require detailed diagnostic skills to pinpoint root causes.
Safety issues – Problems with safety features like triggers, switches and guards require expert assessment and correction to avoid hazards.
Major component replacement – Swapping motors, pumps or other large parts typically involves specialized tools and assembly methods best left to professionals.

Seeking professional service center help the moment a problem seems beyond your basic troubleshooting capabilities will get your pressure washer operating safely once again. Their specialized expertise and diagnostics tools can efficiently zero in on even tricky issues.

Under Pressure!

Pressure washers running at peak performance makes outdoor cleaning tasks far easier. Learning to identify issues quickly and either resolve them yourself or seek professional help prevents small problems from becoming serious equipment failures. Know the common causes of pressure fluctuations, leaks, unusual noises, hot-running, and other problems so you can act promptly. Investing a little effort into proactive maintenance goes a long way towards keeping your pressure washer in reliable working order for years of maximum cleaning productivity.