I have an older Catalina spa that has 2 pumps. One is a 2 speed 4 hp waterway pump and the other is a single speed 4 hp waterway. The single speed waterway is the pump that is giving me problems. I had both these pumps apart to replace the impeller bearings and seals before I started it up with new filters installed. I did notice that the rotor was not in pristine looking condition on the single speed pump when I had it apart but the bearings seemed fine after they were replaced and the rotor turned freely by hand. So I put her back together and started the pool and found that this single speed motor would pump water although at a low flow rate it seemed and in short order I would find it in an over heated condition and turned off by the overheat protection device built into the motor. Since the bearings have been tested and found to be fine and the pump is not kicking the breaker but simply causing the overheat protection to shut the motor down what would you think is the cause of the heating? Could the winding be causing some resistance and therefore heating without causing a breaker to kick? I am going to take the pump out today and ohm out the circuits in the winding to see if they are ok but I don't know of any other cause of this problem. Any suggestions?