The previous owners left a Baracuda Alpha 3 pool cleaner in the pool equipment locker. I finally had an opportunity to pull it out and hook it up. It's about 10 years old, and still works, though I don't know how well as I have nothing to compare it to. It does move around and leaves a clean path on the bottom, but I had it on all day and it didn't go over all the pool bottom.

My question is in the setup. I have a dedicated vacuum port that I connected it to. I primed the hose and the cleaner before I connected it in the port. When I turned off the skimmer and the main so that it would have all the pump power. When did this, the filter pressure dropped to almost 0 and the pump strainer started sloshing and getting air in it. Once I turned the skimmer and main back to flow, it quit and the pressure resumed. I found that I could turn off, either one or the other, (main or skimmer) and the system would work fine, but not if both were shut off. I left the main off so that the pool cleaner wouldn't get stuck on it, and left the skimmer on and it worked fine. It works fine and the hose is always pulsing so I know the internal valve operating in the cleaner. I just don't know why if I just use the vac line it starts sucking air, or where exactly it would be getting air. I should add that the vac port is a good two inches below the water level.

Any ideas or hints I should know? I've been web searching for a manual for the Baracuda Alpha 3 with no success.