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Step by step guide

Go: replace switch box

Servicing our pressure washers are quite straight forward and could be done by most people by following the step-by-step instructions in this manual. Please go trough the whole manual before starting work on your pressure washer to make sure you understand the procedure and that you have the necessary tools to complete the task.

Always unplug the pressure washer from both the mains power and the water outlet before starting the service. Even though power and water is disconnected there may be pressurized water in the hose. Discharge this pressure by pulling the trigger on the gun. Make sure your work area is clean and appropriate for the work you are about to do. There will usually be a small amount of water inside the pump and hose. If you are doing a 10-year service, then be prepared to collect the used oil from the oil chamber. Please dispose of the oil in accordance with local law and regulations. ISO 46 hydraulic oil can be substituted with similar non detergent oil of the same viscosity.

00. Parts and tools

An overview of what is needed to do this service.

01. Remove water filter

Unscrew the water filter then remove it.

02. Remove screws from the front cover

Release the pressure hose from the pump outlet. Unscrew the four T25 screws from the front cover.

03. Remove screws from the tool holder

Turn the pressure washer upside down. Unscrew the two T25 screws from the tool holder.

04. Remove tool holder cover

Remove the bottom of the tool holder cover.

05. Remove front cover

Remove front cover.

06. Remove on/off knob

Remove the on/off button and the power cable strain reliever.

07. Remove screws from the switch box

Unscrew the two T25 screws from securing the switch box and motor/pump assembly.

08. Remove the motor/pump assembly

Carefully lift out the motor/pump assembly.


09. Remove motor cowling

Remove the motor cowling from the motor/pump assembly.

10. Release power cords

Push down the small tab on the female connector while gently pulling the cable. Release both spade connectors from the motor wiring and pull them trough the plastic frame.

11. Remove u-pins

Remove the two U-pins securing the inlet and outlet pipes from the pump head. Use a small flat head screwdriver to pry them loose.

12. Remove inlet and outlet pipe

Remove the inlet and outlet pipes from the pump head.



13. Remove the switch box

Remove the switch box by pulling it in the direction indicated. It is press fitted onto the start/stop valve on the pump.

14. Open the old switch box

If your switch box came without a cable you need to open the old switch box to extract the cable. If your switch box came with a cable you can move on to step 18.

Unscrew the 5 Phillips head screws holding the lid.

15. Extract the power cable

Remove the lid from the switch box.

Release the mains power cable from the main switch. To release the cable, you need to press down the small locking tap on the spade connector.

16. Attach the power cable to the new switch box

Open the lid on your new switch box and connect the mains power cable to the main switch. It does not matter which way you connect it to the main switch as this is alternating current.

Make sure that the sliding and rotating pin is correctly situated before closing the lid.

17. Close the new switch box

Fasten the lid using 5 Phillips head screws.

18. Attach the new switch box

Attach the new switch box to the pump. You need to put a decent amount of pressure to get the box firmly seated on the start/stop valve. It should pop into place.


19. Reattach the inlet and outlet pipe

Reattach the inlet and outlet pipe to the pump head. There is a small notch that secures correct alignment to the pump head.

20. Secure inlet and outlet pipes

Secure the inlet and outlet pipes with two u-pins. You may want to use a small hammer or something similar to lightly tap them into the pump head.

21. Connect the motor power cables

Take the two power cables and pull them trough the plastic frame. Connect the female spade connector to the male spade connector. Give the cables a light tug to check that the connection is secured. The order of the connection is irrelevant since the motor runs on AC power.

22. Refit the motor cowling

Refit the motor cowling, if you removed it.

Turn the motor/pump unit so that the switch box and water inlet is facing up and place it back into the rear cabinet.

23. Place the motor/pump back into the rear cabinet

Turn the motor/pump unit so that the switch box and water inlet is facing up and place it back into the rear cabinet.

24. Secure the motor/pump assembly

Secure the motor/pump and the switch box using the two T25 screws.

25. Attach the on/off knob

Put the on/off knob back on to the switch box.

Fit the power cable strain reliever into the slot.

26. Fit the front cover

Fit the front cover.

Check that the on/off knob can rotate freely.

27. Secure the front cover

Fix the front cover to the back cover by using four T25 screws as indicated.

28. Fit the bottom tool holder cover

Fit bottom tool holder cover.

29. Secure the bottom tool cover

Secure the bottom tool cover using 2 T25 screws.

30. Attach water filter

Check that the filter cassette is clean, then refit the water filter.

31. First start after service

Congratulations with finishing the service of your AVA product.

It is now time to do the first start after service.


  1. Start by connecting the pressure gun to the hose.
  2. Connect water.
  3. Make sure no water is leaking from the inside or anywhere else on the pressure washer.
  4. Pull the trigger and let the water flow until there is no more air coming out.
  5. Connect the power cord.
  6. Turn on the pressure washer.
  7. Pull the trigger and let water run for a minute before connecting a nozzle.
  8. Connect the nozzle. Use the pressure washer and make sure it is operating as normal.

32. Troubleshooting


Water is leaking from the inside

•Disconnect the power and open the pressure washer to locate the leak. Take necessary action to remedy any leaks.

Motor runs and won't stop when you release the trigger

•This is most likely due to an improper seating of the switch box on the start/stop valve. Open the machine and check that the switch box is correctly seated.

The pressure washer won't turn on

•Check that the power cable is connected.

•Check that the circuit breaker has not been tripped.

•Check that the fuse in the power plug is intact (UK models only).

•Open the machine and check that all the internal cabling is connected.

Poor performance/pressure

•Improper assembly or dirt/debris in the pump. Check that the pump and especially the main valve for foreign objects/debris. Make sure that the spring in the main valve is correctly seated and working as intended.