Hopefully I'm in the correct forum. My pool heater which is electric started yesterday and sounded like a very loud wood chipper. I quickly turned off the breaker. The fan was moving and I didn't see that it made contact with anything. The fan however did wobble somewhat on the motor shaft and taking it apart ( fan from motor ) I couldn't see how it could be tightened up any, it wouldn't snug up any more than what the set screw was set for. So as of right now I suspect the motor, am I correct??