Originally Posted by Gayle Quebedeaux
The 5 hp electrical motor that drives the pump for my SPA will not start on low speed. When turned on it hums. I hit the Jet switch and the pump/motor comes on at high speed. I can then hit the Jet switch again and the pump/motor will run on low speed. When the set temperature is reached, the pump/motor shuts off. When the temperature drops, the pump/motor tries to turn on but only hums.
I have replaced the start capacitor and still have the same problem.
Where can I get an explanation of what mechanisims are involved that might be preventing the motor from starting at low speed?