Master: Replace switch box

An overview of what is needed to do this service.

Remove water filter by unscrewing it counterclockwise.

Unscrew the six T25 screws from the back cabinet.

Push the front brace release button and pull the front cover off.

Unscrew the four T25 screws securing the motor/pump.

Release the Cable strain release form the back cabinet.

Carefully lift the motor/pump so that it is on an angle.

Use a flat 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.

Carefully lift out the motor/pump out of the rear cabinet.

Remove the pump head cover and the on/off knob.

Unscrew the small Phillips screw holding the earth cable to the motor housing.

Release the two spade connectors by pushing down on the small tab while gently pulling the two connectors apart.

Rotate the motor/pump so that you gain access to the T25 screw securing 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.

Unscrew the 5 Phillips head screws that secures the switch box cover.

If your switch box comes with mains power cable you can skip ahead to step 22.

Here you can see the 2 different switch boxes that has been used on the Master Series. Top: 2017-2021, bottom: 2021-2023.

The micro switches are different and is therefore not interchangeable. 2017-2021 is a normally closed switch. 2021-2023 is a normally closed switch with roller.

Remove both the micro switch, the main switch and the whole cable assembly from the old switch box.

We will be reusing the mains power cable connected to the main switch.

Remove the mains power cabling by releasing the two spade connectors from the main power switch. Push down the locking tab on the connector and pull gently to release the cable.

Move the mains power cable to the new switch box assembly.

Fit these two spade connectors to the main switch. The colour coding of the wires are irrelevant since this is alternating current.

Place the whole cable and switch assembly back into the switch box. Align the holes in the micro switch with the corresponding protrusions in the switch box cover.

Make sure that the main switch is properly seated in its corresponding slot.

Also check that the small O-ring, the sliders, the spring and the main switch shaft is present and properly positioned.

When you are satisfied with the placement of both cabling and switches, put the switch box lid back on.

Secure the lid using 5 Phillips screws.

Test that the main switch is fully operational by twisting the shaft clockwise and counterclockwise.

There should be an audible click sound as the main switch engages and disengages.

Test the micro switch in a similar fashion by using the U-pin to push on the small slider in the direction of the arrow. There should be an audible click when engaged and a similar click when disengaged.

If any of the switches fails to make a clicking sound, open the switch box to investigate further.

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.

Reattach the two spade connectors to the motor cable. Give them a light tug to check that they are securely locked together.

Reattach the earth cable to the motor.

Secure it using 1 Phillips head screw.

Reattach the pump head cover and the on/off knob.

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.

Make sure that the internal high-pressure hose runs trough these two depressions 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.

If the previous step was successful the motor/pump unit should now fit correctly in the back cabinet.

Reattach the cable strain relief into the slot in back cabinet.

Secure the motor/pump unit using 4 T25 screws. Two screws on top of the motor cowling and two screws on the pump head 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. When you are happy with your alignment, raise the pressure washer to the upright position.

Secure the front cover with six T25 screws from the backside of the pressure washer.

Check that the filter cassette is clean and without damage.

Reattach the water filter to the water inlet.

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

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.