Pressure Washer Troubleshooting Guide

If you own a pressure washer, and you’re all geared up to use it and for some reason, it has a problem, you can do one of two things. Reach for the user manual, or search online. Seeing as you’re here you obviously searched online, and it’s just as well you did.

Because here you’ll find all of the common faults that affect pressure washers along with the easiest cures. From low pressure, motor cut-outs, water leaks, oil leaks, and much more.

So let’s jump straight into the most common pressure washer problems, and how to fix them.

Common Pressure Washer Faults And Fixes

We’ve tried to make this as easy to follow as possible so you can get it fixed and get back on with your pressure washing in as short amount of time as possible.

ProblemProbable causeCure
Low water pressureNot enough water supply to the pressure washerRemove any kinks from the hose, turn the tap on fully, check the hose for blockages, make sure hose diameter is adequate. Check nozzle is correct for use.
Low water pressureBlocked inlet filterRemove hose, clear blockage and reconnect the hose.
No Water pressureFaulty unloader valveCheck for damage, check seals spring, check calibration. Repair or replace as necessary
No water pressureFaulty pumpRemove pump replace or repair
Pulsating water pressureAir blockageTurn off the machine press trigger as water runs through it will remove any air.
Pulsating water pressureFaulty pumpRepair or replace the pump
Pulsating water pressureBlocked nozzleUse the tool provided to clean the nozzle and flush with water
Pulsating water pressureUnloader valve calibrated incorrectlyCheck the user manual for correct calibration and recalibrate
Pressure drops as soon as you start using.Blocked nozzleClean with the tool provided
Pressure drops as soon as you start using.Unloader valve ProblemCheck unloader valve and repair or replace as necessary
Pressure washer working but not cleaningWrong nozzleChange to a higher pressure nozzle
Water pump leakingThermal valve activatedWait 5 minutes and try again
Water pump leakingBolts loose on the pumpRetighten the bolts and make sure casing is fitted together correctly
Water pump leakingDamaged seals, pump crackedReplace pump (contact manufacturer if still on warranty)
Water leaking from the garden hoseBad connectionsReconnect properly or replace washers.
Water leaking from the wandWorn washerReplace the washer
Detergent Injector not workingWrong nozzle Use the black detergent nozzle
Detergent Injector not workingSoap inlet filter blockedFlush with water
Detergent Injector not workingDetergent too thickDilute with more water
Machine louder than normalBlocked water intakeCheck and clean
Machine louder than normalOil level low in the pumpCheck and add oil (if possible) if not contact the manufacturer
Machine louder than normal(Petrol models)Low oil level in the engineCheck and add oil as necessary
Oil leaking from the water pumpLoose boltsRetighten the bolts
Oil leaking from the water pumpDamage to the internal parts of the pumpCheck your warranty and contact the manufacturer or repair and replace.

Common Faults With Electric-Powered Pressure Washers

The following problems only affect electrical pressure washers.

ProblemProbable causeCure
Motor cuts out Low voltageTry moving to a different plug socket and removing any extension cable
The machine doesn’t startNot plugged inPlug it in
The machine doesn’t startSocket switch is offTurn the power supply on
The machine doesn’t startThe power supply is faultyCheck socket, cable, plug, fuse and replace repair or move to a different socket
The machine doesn’t startFaulty motorContact the manufacturer and return under guarantee

Common Faults With Petrol-Powered Pressure Washers

The following problems only affect petrol pressure washers.

ProblemProbable causeCure
Engine won’t startNo fuelFill with the correct fuel
Engine won’t startAir blockUse correct start-up procedure to release air blockage
Engine won’t startChoke and/or throttle needs adjustingAdjust choke and throttle
Engine won’t startFaulty spark plug connectionCheck and reconnect the spark plug wire
Engine won’t startFaulty spark plugRemove, inspect, clean or replace.
Engine cuts out while in useOil level too lowCheck oil level and refill as necessary
Engine cuts out while in useClogged air filterRemove the air filter, clean or renew and replace.
Not enough power from the engineClogged air filterRemove the air filter, clean or renew and replace.
Not enough power from the engineEngine running too slow (or too fast)Check the handbook for specs and adjust engine speed
Oil leaking from the engineWorn sealsCheck the warranty, if you’re not covered replace the seals.
Milky looking oil in the engineWater entering through worn or damaged pistons. Contact manufacturer.

That’s all the common faults you’re likely to come up with while operating (or trying to operate) your pressure washer. You’ll see from the chart above that electric-powered pressure washers have fewer faults to petrol-powered models. That’s not because they are better quality machines, it’s because with a motor replacing the engine, there are fewer working parts to go wrong.

That said, you can’t really repair an electric motor without being an electrician whereas you don’t have to be a mechanic to tinker with a petrol engine (within reason). Also before messing with any parts, or dismantling anything, always check your warranty first. Because once you dismantle anything you run the risk of voiding the warranty.

What’s Better Electric Or Petrol-Powered Pressure washers?

There are pros and cons to each type and it really is down to personal preference. But as a rough guide, here’s a quick comparison chart.

Pros And Cons For Electric-Powered Pressure Washers

Light-weightLower power range
Less maintenanceLimited lifespan
QuieterTies by a cable (less mobility)
Easy to operateColdwater only
A larger choice of attachments
Cheaper purchase price

Pros And Cons For Petrol-Powered Pressure Washers

More powerful PSiHeavier to move
No cables to hold you backCost more to purchase
Considerably longer lifespanHigh maintenance (fuel, oil, filters, spark plug, repairs)
Hot water cleaning powerLouder
More accessibility for repairsHarder to start
Limited range of accessories

For much more information about gas vs electric pressure washers follow this link

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