Karcher pressure washer troubleshooting

When you are faced the breakage of high-pressure water, and absolutely there is no time to ask for help of the repair shops, the table of troubleshooting will help in troubleshooting of serious or simple breakages.
Before you go to a repair shop in case of a malfunction of your pressure washer, read the table of troubleshooting, you may perform the repairs yourself. We have collected the most frequent breakdowns of this device.

Karcher HD 4000 C pressure washer troubleshooting

ProblemPossible CauseRemedy
High-pressure pump fails to come up to pressureLeaking suction-side tubing systemCheck fastener and hose connections
Water starvationCorrect the cause
Defective valve in pump High-pressure solenoid valve fails to closeReplace valves
Pronounced pump knock, pressure gauge pointer oscillatesDefective dash potreplace
With hot-water accessory kit onlyPump is drawing airCheck suction line Replace as required
Defective valve seat or valve springCheck precompression pump
Defective or calcified precompression pump
Overflow volume is blown out into open, and/or safety valve is activatedBlown hose between overflow valve and float valvereplace
Defective overflow valve CAUTION: For safety reasons, excess water is vented outdoors.Repair or exchange overflow valve
Shut down the system!!
Water is returning to float reservoir despite full-volume usageSystem is calcifiedDecalcify system circuits.
Defective spray lances and/or nozzles.Check spray lances Check overflow valve
Defective overflow valve
Overflow valve cycles ON and OFF despite zero usageLeak in high-pressure system, defective spray gun.Repair leak Repair overflow valve
Leaking non-return valve or control piston seal in overflow valve
General fault and “Water supply fault" LED light up on printed circuit boardInsufficient water in float tankCheck site water supply Reduce inlet temperature
Temperature of the water inlet too high
General fault and “HD pump temperature fault” LED light up on printed circuit boardCooling water quantity too low:Clean strainer
Strainer in pressure reduction valve contaminatedRaise pressure Decalcify, replace solenoid valve
Mains water pressure too low
Cooling coil calcified, solenoid valve defective
Oil level too lowCheck oil level
Oil change not made, owing to which there is oil carbon under the piston guide shoes, piston seizing.Check pump parts, replace as necessary. Make an oil change
General fault and “Admission pressure of hot-water pump too low" LED light up. (Only with ABS hot water)Rotation direction of precompression pump wrongChange rotation direction Replace pressure switch
Pressure switch precompression hot-water pump in the ABS hot water defective
Motor fault lights upMotor protection switch Q1 or Q2 has triggered owing to overcurrent or drop-out of one phase of power supply systemCheck voltage of the three phases
Motor protection switch falsely setSet in accordance with circuit diagram
Pressure at pump outlet too highCheck pressure, adjust as necessary
Available time is less than 6 hoursSite high-pressure network is leakySeal it off Replace
Pressure switch defective
System does not start up when unlock button is pressed, no indicator light illuminatesSite power supply interruptedswitch on switch on check
Emergency-STOP master switch offreplace, check cause replace, check
Motor protection switch for control system and precompression pump has been triggered
Control-circuit fuse on transformer defective
Printed circuit board defective, green LED does not blink
System runs for about 15 sec after pressing the unlock button and then switches off. General fault and “Admission pressure of hot-water pump too low" LED light upAdmission pressure of hot water too lowcheck pump rotation direction, check water intake
Pressure switch precompression hot-water pump or cable in ABS hot water defectivereplace
Pump starts during available time but not by opening the handgunPressure switch or cable to pressure switch defectivereplace
Unlock button activated, “operational” indicator light illuminates, system does not start upPressure switch defectivereplace
While activating the HD pistols the unit switches itself offFlow switch does not functioncheck flow switch
Unlock button activated, system starts up, “operational” indicator light does not illuminate“operational” indicator light defectiveswitch Emergency-STOP master switch Q1 to position 0, open control cabinet and verify or replace components
System does not switch onFlow switch S2 defectivereplace upper part of flow switch
Remote start button does not functionSystem in a malfunction stateeliminate the cause and press unlock button

Karcher 1500 G pressure washer troubleshooting

FaultCauseRemedy
Engine will not start- Fuel tank emptyFill fuel tank Open fuel valve
- Fuel valve closed
Unit does not come up to pressure- Pump is sucking air- Open water supply and check garden hose
- Strainer is blocked- Clean strainer
- Pump not bled to remove air- Stop engine, press trigger of gun, start engine and run unit while depressing trigger
- Flow regulation control is set to low pressure- Turn control knob to high pressure
- Pump or relief valve defective- Have unit repaired by authorized service
Water spray irregular- Nozzle clogged- Clean nozzle
- Water supply inadequate- Check to see that water supply is on full force or use stationary water source.
- Relief valve incorrectly set- Have unit repaired by authorized service
No intake of detergent- Nozzle in improper position- Set nozzle to low pressure position
- Detergent metering valve closed- Adjust detergent metering valve to desired setting.
- Suction filter clogged- Clean filter in suction nozzle
- Nozzle clogged- Clean nozzle

Karcher 2400 PSI pressure washer troubleshooting

PROBLEMPOSSIBLE CAUSESOLUTION
LOW OPERATING PRESSUREFaulty pressure gaugeInstall new gauge.
Insufficient water supplyUse larger supply hose; clean filter at water inlet.
Old, worn or incorrect spray nozzleMatch nozzle number to machine and/or replace with new nozzle.
Belt slippageTighten or replace; use correct belt.
Plumbing or hose leakCheck plumbing system for leaks. Retape leaks with teflon tape.
Faulty or mis-adjusted unloader valveAdjust unloader for proper pressure. Install repair kit when needed.
Worn packing in pumpInstall new packing kit.
Fouled or dirty inlet or discharge valves in pumpClean inlet and discharge valves.
Worn inlet or discharge valvesReplace with valve kit.
Obstruction in spray nozzleRemove obstruction.
Leaking pressure control valveRebuild or replace as needed.
Slow engine RPMSet engine speed at proper specifications.
Pump sucking airCheck water supply and possibility of air seepage.
Valves stickingCheck and clean or replace if necessary.
Unloader valve seat faultyCheck and replace if necessary.
BURNER WILL NOT LIGHTLittle or no fuelFill tank with fuel.
Improper fuel or water in fuelDrain fuel tank and fill with proper fuel.
Clogged fuel lineClean or replace.
Plugged fuel filterReplace as needed.
Mis-adjusted burner air bandsReadjust air bands for clean burn.
Little or no fuel pressure from fuel pumpIncrease fuel pressure to specification and/ or replace fuel pump. Test with pressure gauge.
Faulty burner transformerTest transformer for proper arc between contacts. Replace as needed.
Disconnected or short in electrical wiringAll wire contacts should be clean and tight. No breaks in wire
BURNER WILL NOT LIGHTFlex coupling slipping on fuel pump shaft or burner motor shaftReplace if needed.
On-Off switch defectiveCheck for electrical current reaching burner assembly with burner switch on.
Heavy sooting on coil and burner can cause interruption of air flow and shorting of electrodesClean as required.
Improper electrode settingCheck and reset according to diagram in Operator's Manual.
Fuel not reaching combustion chamberCheck fuel pump for proper flow. Check solenoid flow switch on machines with spray gun control, for proper on-off fuel flow control.
Clogged burner nozzleClean as required.
Thermostat faulty or slow engine speedIncrease engine RPM to increase voltage.
Flow switch malfunctionRemove, test for continuity and replace as needed.
Flow solenoid malfunctionReplace if needed.
FLUCTUATING PRESSUREValves worn
Blockage in valveCheck and replace if necessary.
Pump sucking airCheck water supply and air seepage at joints in suction line.
Worn piston packingCheck and replace if necessary.
MACHINE SMOKESImproper fuel or water in fuelDrain tank and replace contaminated fuel.
Improper air adjustmentReadjust air bands on burner assembly.
Low fuel pressureAdjust fuel pump pressure to specifications.
Plugged or dirty burner nozzleReplace nozzle.
Faulty burner nozzle spray patternReplace nozzle.
Heavy accumulation of soot on coils and burner assemblyRemove coils and burner assembly, clean thoroughly.
Misaligned electrode settingRealign electrodes to specifications.
Obstruction in smoke stackCheck for insulation blockage or other foreign objects.
Low engine RPMIncrease RPM
LOW WATER TEMPERATUREImproper fuel or water in fuelReplace with clean and proper fuel.
Low fuel pressureIncrease fuel pressure.
Weak fuel pumpCheck fuel pump pressure. Replace pump if needed.
Fuel filter partially cloggedReplace as needed.
Soot build-up on coils not allowing heat transferClean coils.
WATER TEMPERATURE TOO HOTIncoming water to machine warm or hotLower incoming water temperature.
Fuel pump pressure too highSee specifications for proper fuel pressure.
Fuel pump defectiveReplace fuel pump.
Detergent line sucking airTighten all clamps. Check detergent lines for holes.
Defective temperature switchReplace.
Incorrect fuel nozzle sizeSee specifications for proper fuel nozzle
Insufficient water suppliedCheck water G.P.M. to machine.
Restricted water flowCheck nozzle for obstruction, proper size.
PUMP NOISYAir in suction lineCheck water supply and connections on suction line.
Broken or weak inlet or discharge valve springsCheck and replace if necessary.
Excessive matter in valvesCheck and clean if necessary.
Worn bearings
PRESENCE OF WATER IN OILOil seal wornCheck and replace if necessary.
High humidity in airCheck and change oil twice as often.
WATER DRIPPING FROM UNDER PUMPPiston packing worn
O-Ring plunger retainer worn
Cracked pistonCheck and replace if necessary.
Pump protectorLower water supply pressure. Do not run with spray gun closed longer than 2 minutes
OIL DRIPPINGOil seal worn
EXCESSIVE VIBRATION IN DELIVERY LINEIrregular functioning of the valvesCheck and replace if necessary.
DETERGENT NOT DRAWINGAir leakTighten all clamps. Check detergent lines for holes.
Restrictor in float tank is missingReplace restrictor. Check for proper orifice in restrictor.
Filter screen on detergent suction hose pluggedClean or replace.
Dried up detergent plugging metering valveDisassemble and clean thoroughly.
High viscosity of detergentDilute detergent to specifications.
Hole in detergent line(s)Repair hole.
Low detergent levelAdd detergent, if needed.
PUMP RUNNING NORMALLY BUT PRESSURE LOW ON INSTALLATIONPump sucking airCheck water supply and possibility of air seepage.
Valves stickingCheck and clean or replace if necessary.
Nozzle incorrectly sizedCheck and replace if necessary.
Unloader valve seat faultyCheck and replace if necessary.
Worn piston packingCheck and replace if necessary.
BURNER MOTOR WILL NOT RUNFuel pump seizedReplace fuel pump.
Burner fan loose or misalignedPosition correctly, tighten set screw.
Defective control switchReplace switch.
Loose wireCheck and replace or tighten wiring.
Defective burner motorReplace motor.
RELIEF VALVE LEAKS WATERRelief valve defectiveReplace or repair

Karcher K 1800 IB pressure washer troubleshooting

SymptomCauseSolution
No detergent.Detergent suction tube not properly connected to the machine.Check connection.
Detergent is too thick.Dilute detergent, for best results use Karcher detergent.
Filter on detergent suction tube is clogged.Run warm water through filter to remove debris.
Damaged or clogged detergent suction tube.Remove obstruction or replace detergent suction tube.
Spray wand is in high pressure position.Turn spray wand tip to low pressure position.
Discharge nozzle is obstructed.Blow out or remove debris with a fine needle.
Garden hose connection leaks.Loose fitting.Tighten fittings.
Missing/worn rubber washer.Insert new washer.
Spray wand leaks.Spray wand not properly attached.Insert the spray wand into the trigger gun. Carefully press in against the spring tension and twist into the locked position.
Broken o-ring or plastic insert.Call Karcher customer service hotline and order repair kit.
Pump is noisy.Pump is sucking air.Check that hoses and fittings are air tight. Turn off machine and purge pump by squeezing trigger gun until a steady flow of water emerges through the nozzle.
Water leaks from pump (up to 10 drops per minute is permissible).Loose fittings.Check that all fittings are tight.
Thermal protection device has been activated.Thermal protection device will automatically reset.
Water seals are damaged or worn.Call service center.
Oil Drip.Oil seals are damaged or worn.Call service center.

Karcher HD 2.01000 Ed pressure washer troubleshooting

PROBLEMPOSSIBLE CAUSESOLUTION
PUMP RUNNING NORMALLY BUT PRESSURE LOW ON INSTALLATIONPump sucking airCheck water supply and possibility of air seepage.
Check valves stickingCheck and clean or replace if necessary.
Unloader valve seat faulty
Nozzle incorrectly sized
Worn piston packing
FLUCTUATING PRESSUREValves worn
Blockage in valveCheck and replace if necessary.
Pump sucking airCheck water supply connections.
Worn piston packingCheck and replace if necessary.
Insufficient waterCheck filter and hose for breakage.
PRESSURE LOW AFTER PERIOD OF NORMAL USENozzle worn.
Suction or delivery valves worn
Suction or delivery lines blocked
Unloader valve seat worn
Worn piston packingCheck and replace if necessary.
Water temperature excessiveReduce to below 160° F.
PUMP NOISYAir in suction lineCheck water supply and connections on suction line.
Broken or weak suction or delivery valve springCheck and replace if necessary.
Foreign matter in valvesCheck and clean if necessary.
Worn bearingsCheck and replace if necessary.
Excessive temperature of waterReduce to below 160° F.
PRESENCE OF WATER IN PUMP OILOil seal worn
High humidity in air
Piston packing worn
WATER DRIPPING FROM UNDER PUMPPiston packing worn
O-ring plunger retainer wornCheck and replace if necessary.
WATER DRIPPING FROM PUMP PROTECTORWater supply pressure too high (over 90 PSI)Lower water supply pressure using a regulator.
Spray gun is in the off position for over 5 minutesTurn machine off if not in use for over 1 -2 minutes.
OIL DRIPPINGOil seal worn
EXCESSIVE VIBRATION IN HIGH PRESSURE HOSEIrregular functioning of the pump valvesCheck and replace if necessary.
MOTOR DOES NOT START WHEN SWITCHED ONPlug not well connected or lack of power supplyCheck plug, cable and switch.
WHEN SWITCHING ON THE MACHINE, MOTOR HUMS BUT DOES NOT RUNMain voltage is insufficient, lower than the minimum requiredCheck to make sure main power supply is adequate.
The pump is stuck or frozenCheck by turning the motor manually.
MOTOR STOPSTripped thermal overload due to over- heatingCheck that main voltage corresponds to the specifications. Wait a few minutes before turning on the machine again by resetting the GFCI cord.