Hi all, was just wondering if anyone knew the answer to my problems. Both of my hot tub motors/pumps quit working properly within a week of each other. The problems with each motor/pump were the same. They are 4.5 hp 2 speed A.O. Smith motors. The issue with both is that neither motor/pump will start on Low speed.... they both just hum until they kick out. On both pumps, when its humming on low speed setting, if i hit the button on the control to kick them into high speed, they both will kick into high speed and work perfect. If i switch the pump back to low while the pump impeller is still spinning, they will switch to low and continue to operate properly. If i turn them off and the the impeller stops, the pump will no longer start up on low again, it needs to be bumped to high, then back to low while still spinning to operate.
I replaced the bearing on both motors and the impellers turn extremely easy by hand, no resistance at all. I also replaced the start, and run capacitors on both, and tried a couple different of each, which changed nothing.
To sum it all up, if i bump the pumps on high right at the start they run fine, even if i bump them back to low while the impeller is still moving they continue to run. Once impeller stops, they will no longer cut in on low speed. Tried replacing both start and run capacitors, which did not help.....
Is there something else that may be wrong that anyone is aware of. I took them to repair shop and they tested everything, said everything was good, but they still did not run properly for them and they were completely baffled... maybe someone on here will have had experience with this???
Any help is appreciated