Originally Posted by pumpguy
You would be surprised. I have had them working that way for years. They just won't build enough pressure to shut off.
It would be wired incorrectly to run on 120 would not just happen.
If you loose one leg, you loose connection to make the loop back to the other breaker. It would have had to fry a connection and then make connection with ground and or nuetral if one is there. I guess that could happen , easy to prove by removing one leg and then the other to see if it will run on one leg.
I would be more suspect of the motor running outside it's voltage limits for some time, a stressed motor may not be able to take the shock of an interupted cycle, when the power went off.