Polaris 380 Tune Up Not Moving in Water


New member
Jul 24, 2019
Wynnewood PA
Hello, looking for help. I just rebuilt my old Polaris 380 with a tune up kit. It had a broken belt but I replaced all the parts except for base assembly, frame, water management pipes and a few other minor components. All wheels, bearings, rods, turbines, etc were replaced. Everything appears to be in place and working (I've taken it apart several times to check for leaks, weight, blockages, etc).

I have a newer booster pump. I replaced pressure valve and connection to wall valve. When Polaris is out of the water the wheels spin very fast but when the Polaris is submerged in water it barely spins and spins faster while on its side but when upright almost stops. It will VERY slowly crawl the floor of the pool but will not climb or move very well at all. This is so frustrating because the polaris looks brand new and I've taken it apart so many times to triple check all the connections.

Are there any tricks or small things i am missing? I even removed the backup device from the white hose to rule out the backup being defective. The pressure relief valve does open some from the pressure but isn't that normal.

Any help or support is much appreciated!


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Replace the water management system. Those pipes provide the motive power. It is hard to examine them closely and see where it may be clogged or split.

It is either the WMS or friction on some rotating parts.
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