The machine pulses, either in standby or in use.

There can be various reasons why washers pulsate, whether in use or in standby. Feel free to go through the troubleshooting form to see if that guides you to the correct solution.

Pulsation can cause the machine to overheat, or in the case of our UK customers, blow the 13A fuse in the plug.

The machine pulses in standby:

Check if there is a leak on the machine's high-pressure side:

1. Place the machine on a dry surface. Concrete or cardboard/paper are best as it is easy to detect leaks on these surfaces.

2. Unroll all the hose from the drum.

3. Only have the gun connected to the hose, no nozzles or lances.

4. Connect water and electricity and switch on the washer. Flush until the pump and hose are empty of air.

5. Shake the gun slightly to empty the injector of water. Look into the injector (the tube that goes into the nozzles/lances in the "gun mouth") and see if it slowly fills up. If it does, the problem is the valve in the gun.
6. Go over the entire hose and see if any water is leaking from the hose itself. These leaks are usually very visible.

7. Then check if there is any leakage inside the swivel on the drum, where the hose is connected to the drum. The connections between the hose and the gun should also be checked.

8. Finally, check if any water has leaked out from under or around the machine. The frequency of the pulsation says something about how big the leak is. If there are very long stays between the pulses (20 seconds or longer), it can be difficult to locate visually. The best thing then is to set the machine, hose and gun as described in point 1 above and look for wet spots.

If you cannot locate the leak, proceed to the troubleshooting form.

The machine pulses during use:

Start by checking that the nozzle fits the washer. (Read more about nozzle markings in our Choosing the right nozzle article.) Remove any lance and nozzle, and try using using the machine with no attachments beyond the gun.

If not, then the reason why the washer pulsates is probably the switching on and off of a relief valve. It sits on top of the pump, and is what turns the pump on and off. When the pressure exceeds a given value, this valve will activate a switch in the electric box that cuts the power to the motor. When the pressure drops again, the valve will fall back to its rest position and restart the engine. A sticky relief valve can often be rectified simply by cycling some WD-40 through the pump.

If this doesn't work, go to troubleshooting form.

We are currently working on translating and rewriting all of our articles into English from the original Norwegian. Whilst we are proud of the quality of our language skills here at AVA, we are aware that there may be some slightly odd syntax and wording present in the articles that have been translated. The approach we have taken to this translation process is in order to get as much information as possible out to our customers in a timely fashion. Thusly the ongoing revision and updating of these articles by our British-Norwegian team will include slight changes to how the text is put together in order to bring it more into line with correct British English.