Thought I had the common cavitation issues, but I think its something else.
Pumping hot liquids you'll be going along fine and then hear a short squeal/buzz, motor changes pitch slightly and all flow stops. I shut the pump off and let the motor spool down. Just before the motor stops it lets out another squeal/buzz. Only then can you switch the pump back on and repeat the process again.
Pump outlet is connected to a tee with a ball valve to drain the system. When pump's acting up I can open the valve and gravity feed through the pump to drain. That makes me think the impeller isn't spinning at all despite the motor humming along. On a desperate whim I greased the impeller shaft with silicon. Bingo! Although the problem didn't completely go away, performance greatly improved. For whatever reason the impeller must be seizing up and decoupling from the magnet. The components will not recouple unless everything comes to a stop.
Ideas on why and how can I fix it?
Pumping hot liquids you'll be going along fine and then hear a short squeal/buzz, motor changes pitch slightly and all flow stops. I shut the pump off and let the motor spool down. Just before the motor stops it lets out another squeal/buzz. Only then can you switch the pump back on and repeat the process again.
Pump outlet is connected to a tee with a ball valve to drain the system. When pump's acting up I can open the valve and gravity feed through the pump to drain. That makes me think the impeller isn't spinning at all despite the motor humming along. On a desperate whim I greased the impeller shaft with silicon. Bingo! Although the problem didn't completely go away, performance greatly improved. For whatever reason the impeller must be seizing up and decoupling from the magnet. The components will not recouple unless everything comes to a stop.
Ideas on why and how can I fix it?