This step-by-step guide shows how to change switch box on your AVA Master P60-P80, both Master 1.0 and Master 2.0.
The procedure is the same if the issue is identified as the micro switch.
The service itself doesn’t involve many steps, but each one is described in detail to make the process as easy as possible for you – and to ensure the best possible result. We recommend reading through all the steps before you begin, so you understand the procedure and have the necessary tools to complete the task.
Always unplug the pressure washer from both the mains power and the water inlet before starting the service.
Click here to read our article regarding safety
Even though power and water are disconnected there may be pressurized water in the hose. Discharge this pressure by pulling the trigger on the gun in a safe direction.
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.
01. Remove water filter
Unscrew the water filter.
02. Remove screws from the back cabinet
Unscrew 6 T25 screws from the back cabinet. (Picture 1)
Note: Machines produced in 2024 or later have 3 extra screws in addition to picture 1. (Picture 2)
Picture 1:
Picture 2 (Master produced in 2024 or later):
03. Remove the front cover
Push the front brace release button and pull the front cover off.
04. Remove screws from the motor/pump
Unscrew 4 T25 screws securing the motor/pump.
05. Release cable strain relief
Release the cable strain relief from the cabinet.
06. Lift the motor/pump unit
Carefully lift the motor/pump so that it is on an angle.
07. Release the internal hose
Carefully use a flathead screwdriver or a small knife to release the U-pin securing the internal hose to the pump outlet.
Pull the hose from the pump head.
08. Lift the motor/pump
Carefully lift the motor/pump out of the rear cabinet.
09. Remove parts
Remove the pump head cover and the on/off knob.
10. Remove grounding cable
Unscrew the small Phillips screw holding the earth cable to the motor housing.
11. Disconnect motor cabling
Release the two spade connectors by pressing down on the small tab and gently pulling them apart.
12. Remove screw from switch box
Rotate the motor/pump so that you gain access to the T25 screw securing the switch box.
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. Attach the new switch box to the pump
Attach the switch box to the pump. It requires a fair amount of pressure to get the box firmly seated on the start/stop valve. It should pop into place.
Secure the switch box with a T25 screw.
15. Attach motor cabling
Reattach the 2 spade connectors to the motor cable. Give them a light tug to check that they are securely locked together.
16. Attach the grounding cable
Reattach the grounding cable to the motor.
Secure it using 1 Phillips head screw.
17. Attach on/off knob and pump head cover
Reattach the pump head cover and the on/off knob.
18. Attach the internal pressure hose
With the motor/pump at an angle, reattach the internal high-pressure hose to the pump head.
Secure the hose using a U-pin. Some force may be needed to properly secure the U-pin to the pump head.
19. Align the internal pressure hose
Make sure that the internal high-pressure hose runs through these two grooves in the back cabinet (red arrows). If you are unable to fit the motor/pump properly then lift it up and check that the internal hose runs as indicated in this picture.
20. Align the motor/pump
If the previous step was successful the motor/pump unit should now fit correctly in the back cabinet.
21. Attach the cable strain relief
Reattach the cable strain relief into the slot in back cabinet.
22. Secure the motor/pump
Secure the motor/pump using 4 T25 screws. 2 screws on top of the motor cowling and 2 screws on the pump head cover.
23. Attach the front cover
Put the front cover back onto the pressure washer. This is easiest with the pressure washer lying flat. A bit of work may be needed to get it to align perfectly with the back cabinet, take your time. Push the front brace release button to allow for a correct alignment of the brace.
Once you are happy with your alignment, raise the pressure washer to the upright position.
24. Fasten the front cover
From the backside of the pressure washer, secure the front cover with 6 T25 screws (Picture 1)
Remember the 3 extra screws in addition if you have Master produced in 2024 or later. (Picture 2)
Picture 1:
Picture 2 (for Master produced in 2024 or later):
25. Reattach the water filter
Check that the filter cassette is clean and without damage. (The cassette can be removed for cleaning)
Reattach the water filter to the water inlet.
26. First start after service
It is now time to do the first start after service.
- Start by connecting the pressure gun to the hose.
- Connect water. Ensure that no water is leaking from inside the pressure washer or elsewhere.
- Pull the trigger and let the water flow until there is no more air coming out.
- Connect the power cord.
- Turn on the pressure washer.
- Pull the trigger and let water run for a minute before connecting a nozzle.
- Connect the nozzle.
- Use the pressure washer and make sure it is operating as normal.
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.
Motor is making a humming noise and is not able to start
- Check that the capacitor is connected to the motor.
- It should be connected with one white and one black cable.
