Ok, I got it. I tried to do it directly on the OpenSprinkler by long pressing B3 (or is it E3), short pressing B3 and then long pressing B3. That should have started the 1 minute test program. But as soon as I did the second long press on B3 the unit would reboot. I ended up trying another power adapter (12V/1.5A) and now it works just fine. I then tried the web portal and that worked as well. It shows a current of about 245mA. Since I only run one zone at a time that 1.5A adapter should be fine.