Pump doesn't come back on

[Badambomb79]

I have a sump under my tank and a pump to get the water back up into the tank. Anyways whenever I unplug the pump for water changes or what not. When I plug the pump back in it doesn't turn back on sometimes I have to take the impeller out and put it back in to get it to work again. What am I supposed to do to get this thing to turn on when I plug it in?

 

[Crazyhermitcrab]

I have a sump under my tank and a pump to get the water back up into the tank. Anyways whenever I unplug the pump for water changes or what not. When I plug the pump back in it doesn't turn back on sometimes I have to take the impeller out and put it back in to get it to work again. What am I supposed to do to get this thing to turn on when I plug it in?

Post a picture or tell me the model.