Having a similar problem here with a 6 week old Dolphin Nautilus CC Plus. Except for mine only goes about 15-30 seconds. Looks to be failing the self-test. Filters are clean.....and I cannot get the darn impeller cover off. They have a little screw post that you are supposed to rotate 45 degrees CCW and the impeller cover is supposed to open. Well, I cannot get the screw post to rotate more than 10 degrees. Calling Maytonics tomorrow. It's possible if the impeller is clogged up, it will fail self-test. Been real happy with the results, granted there are a few quirks, overall since I bought it. I was planning on writing a comprehensive review, will wait till problem resolved.