I moved a few years ago and always accepted that the Polaris 380 that came with the house did an OK job at best. I always seems to miss spots and whenever the hose gets even the slightest bit tangled it doesn't have the power to untangle it (as a result it generally doesn't get very far).
I did some research for this season and decided to figure out whats wrong with it. Sounds like the wheels should be running at 28-32 RPM - I'm at 20. My initial reaction is it must be a pressure issue. The pressure relief value always had a good amount of water coming out of it (even when fully tightened). I replaced it with a new one - no change in wheel RPM. The new one still leaks a bit, but it's not as bad as the old one.
I also noticed that the backup value has water coming out of it even when it's not on the backup cycle. I replaced the backup value. While the new value still has some water that comes out of it all the time it's not nearly as much as what was coming out before.
After these two repairs I've gone from 20rpm to 21 or 22 - basically no change. Any ideas on what else I should be looking for? I've also disassembled the thing and cleaned out the tiny jet (using a paper clip) that powers the wheels (so I believe it's getting full power in that regard).