I posted a few days back about how I'd just done a total rebuild on our Polaris 380, and that it seemed to be working great. Turned out that I'm still having a problem that is leaving me a bit puzzled. Frequently when I go out to check the pool, the Polaris seems to be stuck and not moving other than when the back-up unit does it's cycle.
If I fish it out (after turning off the pumps, I find the wheels don't want to turn, but if I apply just a little force, the wheels break loose and start turning freely again. If I put the unit back in the pool, and turn the pumps back on, it again seems to be working fine.
Earlier this week, I opened the cleaner back up, and found a fairly large amount of coarse sand in the inner body of the unit. It looks to me like the sand may be getting into the gears occasionally and providing just enough of a jamming force to stop the unit. Does this sound like it is the problem? When there is nothing in the gears it feels nice and smooth when I turn the wheels by hand, or manually spin the turbine wheel.
The big question I have though is where is the sand coming from? The water supply to the unit is coming from the booster pump, which is feeding from the output side of our DE filter. There is no sign of DE in the pool, like there has been when I had a hole in the filter at other times. In addition, as far as I know the little stainless filter in the wall fitting is there, and in good shape. (I can't currently double check this as I can't reach the fitting from my chair...) The pool water that is going through the vacuum never touches the inside of the unit, only the water coming from the pump via the "water management system".
Leaves me with the two questions, of where is the sand coming from / how is it getting into the unit And how do I stop it from getting into the gears