The pressure washer has stopped working – how can I fix it?

Has your outdoor cleaning equipment decided to go on strike and refuse to start? A Karcher, Nilfisk or Bosch pressure washer that won’t start or only works half the time is often hiding a minor technical fault. The power cable, switch, capacitor, motor brushes, pump or filter… several components could be causing this fault. Identifying the faulty part, understanding the symptom and knowing which solution to apply are the key steps to restoring your pressure washer to full, reliable working order.

THE POTENTIAL CAUSES FOR THIS FAULT:

• A problem with the mains socket

• The power cable is faulty

• The switch is no longer working

• The capacitor is faulty

• The motor brushes are worn

• The pump is damaged

• The filter is blocked

WARNING
Before you do anything to your appliance, make sure you disconnect it from the power supply.
There is a risk of electric shock.
Wear suitable protective gloves if you need to dismantle anything.
There is a risk of getting cut or injured.

A problem with the mains socket

The power socket supplies your high-pressure cleaner with electricity. If it is faulty or incorrectly connected, the appliance will not receive any power and will not start. Before dismantling your steam cleaner, check the socket with another appliance or test it with a multimeter (set it to the highest range in AC mode; you should read a value close to 230 volts). Also check that the socket is not damp or burnt.

The power cable is faulty

The cable carries electricity to the motor. If it is cut, pinched or worn, the electrical current is interrupted, which may prevent the cleaner from switching on or cause it to operate intermittently. Before replacing it, you can test the cable using a multimeter by checking the continuity of the current between the plug and the motor. You should obtain a reading close to 0 Ω. If the multimeter reads 1 or OL, this confirms that the cable is faulty. In this case, it is important to replace the cable, ensuring that it is properly insulated and suitable for use in damp conditions.

The switch no longer works

The on/off switch controls the motor. When it is worn, dirty or damaged, the electrical contact may be broken, preventing the machine from starting. To resolve this issue, it is advisable to clean the switch thoroughly or, if necessary, replace it to restore the contact and ensure proper operation.

The capacitor is faulty

The start-up aid component in your high-pressure cleaner provides the electrical impulse needed to start the motor. If it is faulty, the motor may fail to start and produce nothing more than a humming noise. To resolve this issue, it is recommended that you replace the interference filter, ensuring you strictly adhere to the voltage and capacitance specified on the part to ensure a safe and effective start.

Buy a high-pressure washer capacitor

The motor brushes are worn

The motor carbon brushes allow electrical current to reach the rotor and power your high-pressure cleaner’s motor. When they are too worn, the motor may run unevenly, start intermittently or stop completely. If your motor brushes are worn, they will need to be replaced to repair your cleaning equipment.

The pump is damaged

The pump in your high-pressure washer is the component that generates the pressure needed to spray water with force. If it is damaged – whether due to seizure, worn seals or valves – the machine may lose all pressure or fail to start. Before replacing it, it is advisable to check that there are no foreign objects and to bleed the pump to remove any air or residue. If a fault is confirmed, the pump or its internal components will need to be replaced, depending on the diagnosis, to restore optimal operation.

Buy a high-pressure washer pump

The filter is blocked

The filter in your high-pressure washer protects the pump from impurities in the water, such as sand or deposits. If it is blocked or clogged, the water does not flow properly, which can cause a loss of pressure or prevent the motor from starting on certain models. To resolve this issue, we recommend cleaning the filter regularly with clean water and replacing it if the mesh is damaged. Keeping the filter clean helps to restore flow and pressure.