Karcher pressure washer troubleshooting: not working and not starting Karcher

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

Problem	Possible Cause	Remedy
High-pressure pump fails to come up to pressure	Leaking suction-side tubing system	Check fastener and hose connections
	Water starvation	Correct the cause
	Defective valve in pump High-pressure solenoid valve fails to close	Replace valves
Pronounced pump knock, pressure gauge pointer oscillates	Defective dash pot	replace
With hot-water accessory kit only	Pump is drawing air	Check suction line Replace as required
	Defective valve seat or valve spring	Check precompression pump
	Defective or calcified precompression pump
Overflow volume is blown out into open, and/or safety valve is activated	Blown hose between overflow valve and float valve	replace
	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 usage	System is calcified	Decalcify 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 usage	Leak 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 board	Insufficient water in float tank	Check 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 board	Cooling water quantity too low:	Clean strainer
	Strainer in pressure reduction valve contaminated	Raise pressure Decalcify, replace solenoid valve
	Mains water pressure too low
	Cooling coil calcified, solenoid valve defective
	Oil level too low	Check 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 wrong	Change rotation direction Replace pressure switch
	Pressure switch precompression hot-water pump in the ABS hot water defective
Motor fault lights up	Motor protection switch Q1 or Q2 has triggered owing to overcurrent or drop-out of one phase of power supply system	Check voltage of the three phases
	Motor protection switch falsely set	Set in accordance with circuit diagram
	Pressure at pump outlet too high	Check pressure, adjust as necessary
Available time is less than 6 hours	Site high-pressure network is leaky	Seal it off Replace
	Pressure switch defective
System does not start up when unlock button is pressed, no indicator light illuminates	Site power supply interrupted	switch on switch on check
	Emergency-STOP master switch off	replace, 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 up	Admission pressure of hot water too low	check pump rotation direction, check water intake
	Pressure switch precompression hot-water pump or cable in ABS hot water defective	replace
Pump starts during available time but not by opening the handgun	Pressure switch or cable to pressure switch defective
Unlock button activated, “operational” indicator light illuminates, system does not start up	Pressure switch defective
While activating the HD pistols the unit switches itself off	Flow switch does not function	check flow switch
Unlock button activated, system starts up, “operational” indicator light does not illuminate	“operational” indicator light defective	switch Emergency-STOP master switch Q1 to position 0, open control cabinet and verify or replace components
System does not switch on	Flow switch S2 defective	replace upper part of flow switch
Remote start button does not function	System in a malfunction state	eliminate the cause and press unlock button

Karcher 1500 G pressure washer troubleshooting

Fault	Cause	Remedy
Engine will not start	- Fuel tank empty	Fill 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

PROBLEM	POSSIBLE CAUSE	SOLUTION
LOW OPERATING PRESSURE	Faulty pressure gauge	Install new gauge.
	Insufficient water supply	Use larger supply hose; clean filter at water inlet.
	Old, worn or incorrect spray nozzle	Match nozzle number to machine and/or replace with new nozzle.
	Belt slippage	Tighten or replace; use correct belt.
	Plumbing or hose leak	Check plumbing system for leaks. Retape leaks with teflon tape.
	Faulty or mis-adjusted unloader valve	Adjust unloader for proper pressure. Install repair kit when needed.
	Worn packing in pump	Install new packing kit.
	Fouled or dirty inlet or discharge valves in pump	Clean inlet and discharge valves.
	Worn inlet or discharge valves	Replace with valve kit.
	Obstruction in spray nozzle	Remove obstruction.
	Leaking pressure control valve	Rebuild or replace as needed.
	Slow engine RPM	Set engine speed at proper specifications.
	Pump sucking air	Check water supply and possibility of air
	Valves sticking	Check and clean or replace if necessary.
	Unloader valve seat faulty	Check and replace if necessary.
BURNER WILL NOT LIGHT	Little or no fuel	Fill tank with fuel.
	Improper fuel or water in fuel	Drain fuel tank and fill with proper fuel.
	Clogged fuel line	Clean or replace.
	Plugged fuel filter	Replace as needed.
	Mis-adjusted burner air bands	Readjust air bands for clean burn.
	Little or no fuel pressure from fuel pump	Increase fuel pressure to specification and/ or replace fuel pump. Test with pressure gauge.
	Faulty burner transformer	Test transformer for proper arc between contacts. Replace as needed.
	Disconnected or short in electrical wiring	All wire contacts should be clean and tight. No breaks in wire
BURNER WILL NOT LIGHT	Flex coupling slipping on fuel pump shaft or burner motor shaft	Replace if needed.
	On-Off switch defective	Check 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 electrodes	Clean as required.
	Improper electrode setting	Check and reset according to diagram in Operator's Manual.
	Fuel not reaching combustion chamber	Check fuel pump for proper flow. Check solenoid flow switch on machines with spray gun control, for proper on-off fuel flow control.
	Clogged burner nozzle	Clean as required.
	Thermostat faulty or slow engine speed	Increase engine RPM to increase voltage.
	Flow switch malfunction	Remove, test for continuity and replace as needed.
	Flow solenoid malfunction	Replace if needed.
FLUCTUATING PRESSURE	Valves worn
	Blockage in valve	Check and replace if necessary.
	Pump sucking air	Check water supply
	Worn piston packing	Check and replace if necessary.
MACHINE SMOKES	Improper fuel or water in fuel	Drain tank and replace contaminated fuel.
	Improper air adjustment	Readjust air bands on burner assembly.
	Low fuel pressure	Adjust fuel pump pressure to specifications.
	Plugged or dirty burner nozzle	Replace nozzle.
	Faulty burner nozzle spray pattern	Replace nozzle.
	Heavy accumulation of soot on coils and burner assembly	Remove coils and burner assembly, clean thoroughly.
	Misaligned electrode setting	Realign electrodes to specifications.
	Obstruction in smoke stack	Check for insulation blockage or other foreign objects.
	Low engine RPM	Increase RPM
LOW WATER TEMPERATURE	Improper fuel or water in fuel	Replace with clean and proper fuel.
	Low fuel pressure	Increase fuel pressure.
	Weak fuel pump	Check fuel pump pressure. Replace pump if needed.
	Fuel filter partially clogged	Replace as needed.
	Soot build-up on coils not allowing heat transfer	Clean coils.
WATER TEMPERATURE TOO HOT	Incoming water to machine warm or hot	Lower incoming water temperature.
	Fuel pump pressure too high	See specifications for proper fuel pressure.
	Fuel pump defective	Replace fuel pump.
	Detergent line sucking air	Tighten all clamps. Check detergent lines for holes.
	Defective temperature switch	Replace.
	Incorrect fuel nozzle size	See specifications for proper fuel nozzle
	Insufficient water supplied	Check water G.P.M. to machine.
	Restricted water flow	Check nozzle for obstruction, proper size.
PUMP NOISY	Air in suction line	Check water supply and connections on suction line.
	Broken or weak inlet or discharge valve springs	Check and replace if necessary.
	Excessive matter in valves	Check and clean if necessary.
	Worn bearings
PRESENCE OF WATER IN OIL	Oil seal worn	Check and replace if necessary.
	High humidity in air	Check and change oil twice as often.
WATER DRIPPING FROM UNDER PUMP	Piston packing worn
	O-Ring plunger retainer worn
	Cracked piston	Check and replace if necessary.
	Pump protector	Lower water supply pressure. Do not run with spray gun closed longer than 2 minutes
OIL DRIPPING	Oil seal worn
EXCESSIVE VIBRATION IN DELIVERY LINE	Irregular functioning of the valves	Check and replace if necessary.
DETERGENT NOT DRAWING	Air leak	Tighten all clamps. Check detergent lines for holes.
	Restrictor in float tank is missing	Replace restrictor. Check for proper orifice in restrictor.
	Filter screen on detergent suction hose plugged	Clean or replace.
	Dried up detergent plugging metering valve	Disassemble and clean thoroughly.
	High viscosity of detergent	Dilute detergent to specifications.
	Hole in detergent line(s)	Repair hole.
	Low detergent level	Add detergent, if needed.
PUMP RUNNING NORMALLY BUT PRESSURE LOW ON INSTALLATION	Pump sucking air	Check water supply and possibility of air
	Valves sticking	Check and clean or replace if necessary.
	Nozzle incorrectly sized	Check and replace if necessary.
	Unloader valve seat faulty
	Worn piston packing
BURNER MOTOR WILL NOT RUN	Fuel pump seized	Replace fuel pump.
	Burner fan loose or misaligned	Position correctly, tighten set screw.
	Defective control switch	Replace switch.
	Loose wire	Check and replace or tighten wiring.
	Defective burner motor	Replace motor.
RELIEF VALVE LEAKS WATER	Relief valve defective	Replace or repair

Karcher K 1800 IB pressure washer troubleshooting

Symptom	Cause	Solution
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

PROBLEM	POSSIBLE CAUSE	SOLUTION
PUMP RUNNING NORMALLY BUT PRESSURE LOW ON INSTALLATION	Pump sucking air	Check water supply and possibility of air
	Check valves sticking	Check and clean or replace if necessary.
	Unloader valve seat faulty
	Nozzle incorrectly sized
	Worn piston packing
FLUCTUATING PRESSURE	Valves worn
	Blockage in valve	Check and replace if necessary.
	Pump sucking air	Check water supply connections.
	Worn piston packing	Check and replace if necessary.
	Insufficient water	Check filter and hose for breakage.
PRESSURE LOW AFTER PERIOD OF NORMAL USE	Nozzle worn	.
	Suction or delivery valves worn
	Suction or delivery lines blocked
	Unloader valve seat worn
	Worn piston packing	Check and replace if necessary.
	Water temperature excessive	Reduce to below 160° F.
PUMP NOISY	Air in suction line	Check water supply and connections on suction line.
	Broken or weak suction or delivery valve spring	Check and replace if necessary.
	Foreign matter in valves	Check and clean if necessary.
	Worn bearings	Check and replace if necessary.
	Excessive temperature of water	Reduce to below 160° F.
PRESENCE OF WATER IN PUMP OIL	Oil seal worn
	High humidity in air
	Piston packing worn
WATER DRIPPING FROM UNDER PUMP	Piston packing worn
	O-ring plunger retainer worn	Check and replace if necessary.
WATER DRIPPING FROM PUMP PROTECTOR	Water supply pressure too high (over 90 PSI)	Lower water supply pressure using a regulator.
	Spray gun is in the off position for over 5 minutes	Turn machine off if not in use for over 1 -2 minutes.
OIL DRIPPING	Oil seal worn
EXCESSIVE VIBRATION IN HIGH PRESSURE HOSE	Irregular functioning of the pump valves	Check and replace if necessary.
MOTOR DOES NOT START WHEN SWITCHED ON	Plug not well connected or lack of power supply	Check plug, cable and switch.
WHEN SWITCHING ON THE MACHINE, MOTOR HUMS BUT DOES NOT RUN	Main voltage is insufficient, lower than the minimum required	Check to make sure main power supply is adequate.
	The pump is stuck or frozen	Check by turning the motor manually.
MOTOR STOPS	Tripped thermal overload due to over- heating	Check that main voltage corresponds to the specifications. Wait a few minutes before turning on the machine again by resetting the GFCI cord.