Yesterday I fixed my Bestway Lay Z Spa. It gave the infamous E02.
Opening up the thing it was. Because in a video the guy explained about the water flow sensor being a magnetic switch I decided to try taking the sensor itself out of the component. Then I tried with a external magnet to get the detached switch to close. The error was gone and I could make the motor run without any water flowing. That’s probably not a great idea if you don’t want to damage anything. So, of course, I didn’t do that for too long.
However. When I reinserted the sensor into the component, and closed the valve myself, the ER02 error did still happen. I figured the magnet that gets pushed to the ceiling of the component was somehow weakened.
Then I noticed a little notch on it. I marked it in a red circle:
I decided to take a flat file and file it off. When I now closed the valve myself, I could just like with the magnet make the motor run without any water flowing.
I reassembled it all. Reattached the device to the bath tube. It all works. Warm water this evening! I hope there will be stars outside.