Pressure washer won’t start

If a pressure washer won’t starts, there are two possibilities. The unit can generally no longer be put into operation or it stops during a short spraying break and no longer starts automatically. There are several causes for both phenomena, ranging from very banal reasons to technical defects.

Isolate and rule out possible reasons around the unit

The reasons for the motor of a pressure washer not starting after switching on are often banal. Often they lie outside the unit.

Therefore, the following possibilities should be checked first and the reasons excluded:

  • The socket has no power
  • A fuse has blown or switched off.
  • The cable is broken or torn
  • The cross-section of the extension cable is too small (2.5mm²).

Also of interest: Why does the gun on a pressure washer leak?

Causes in the technology and in the unit

When looking for defects in the unit, it helps to keep in mind how a high-pressure cleaner works. Roughly simplified and in layman’s terms, the pump unit has a compression circuit similar to that of a petrol engine (car). This circumstance results in the following possible causes of faults that prevent the unit and the engine from starting:

  • The defective pressure switch does not trip on “compression”.
  • The pressure switch does not receive the necessary pressure because there is air in the system.
  • The control piston is dirty and jammed
  • Valves are clogged and take the “breath” out of the circuit

A fault not directly related to the functional system can be a defective on/off switch.

Also of interest: Repairing the pump yourself in the pressure washer

Reasons for failure to restart automatically

A pressure washer is triggered by pulling the gun trigger and switched off by releasing it. When it switches off, the resulting pressure in the pressure pipe ensures that the pressure switch “leaves the motor switched off”. When the pressure is “released” again by opening the gun, it automatically switches the motor on again. The following technical reasons hinder or prevent this automatism:

  • Air in the system
  • Insufficient or no pressure build-up
  • The high-pressure cleaner stutters

More on the topic: Pressure Washer Repair

The manufacturer’s operating instructions or spare parts list can be used to identify potentially suspect damaged components. Especially in the case of seals and valves, malfunctions can also be caused by wear.

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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