Pressure washer no longer turns off automatically

During normal operation, the pump in the pressure washer switches off when the gun is closed. If the unit does not then switch off automatically, something is wrong with the pressure build-up. The pressure increase gives the pressure switch the signal to close and switch off the pump. A leakage or a defective valve are common causes.

Rising pressure interrupts the power supply to the pump

The pressure created in the high-pressure cleaner by the compression of air has a control function at the same time as the desired water jet. Inside, valves detect the pressure and react accordingly. If the pressure rises after the gun has been closed, the pressure switch interrupts the power supply to the pump. If the gun is opened again by pulling the trigger, the pressure drops and the pressure switch switches the power supply to the pump back on.

If insufficient or no pressure builds up in the pressure washer, one of the following causes is present:

Leakage

The circuit is no longer tight and has a leak or leaks. The leak can be in several places in the system:

  • Hose
  • Hose connections or connecting pieces
  • Seals at the hose connections (causes not only blow-off and water leakage, but also the drawing in of air, which reduces the pressure)
  • Gun

Also of interest: Why does the pressure washer stutter?

Pressure switch or valves

Valves or the pressure switch do not react properly because they are defective or dirty.

  • Pump and suction valves
  • Valve piston chambers
  • Pressure switch (defect usually additionally recognisable by water leakage)
  • Check valve
  • Cover of the piston chambers
  • Defective switching relay does not transmit the impulse from the pressure switch

Also of interest: Why does my pressure washer keep pulsing?

Contamination

The functionality of all components can be impaired or prevented by dirt deposits such as limescale and cleaning agent residues. In many cases, thorough cleaning will help to restore the switching mechanism to working order.

Also of interest: Pressure Washer Repair and Troubleshooting – Solutions to Common Problems

Bridged current flow

Wetness in the unit or a detached cable “bridges” the current interruption. If this is the cause, the unit must be properly repaired before any further operation, otherwise current flow to the outside is possible.

A more indirect reason why the pressure build-up does not have the necessary controlling effect is an insufficient water supply. In most cases, however, this manifests itself before the circuit fault through the failure of the spray function or other malfunctions.

Alfred Harper

Alfred Harper

Alfred Harper is a former consultant and product expert at a company producing cleaning equipment. He was working at this position for more than 10 years and has gained incredible experience and knowledge as he has tested almost all pressure washers brands and models and became an expert in this field. Now, he is writing reviews and how-to articles about pressure washers and makes a great contribution to the Pressure Washers company to help people to choose the best cleaning equipment for home use.

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