My sump pump is running constantly without water...what can I try before buying a new one?
Sump pumps have a float switch that controls the pump motor when water enters the pump well. Your float switch may be hung up on the side of the well or debris has gotten into the well and is keeping the float elevated, causing the pump to run.
Just buy new one. :p
It might be that the motor is just humming but not running. This problem can also occur if the pump is air-locked, check valve is stuck closed, or the impeller is damaged among other problems. Check out the details on www.tractorsupply.com/know-how_Pumps_sump-pump-troubleshooting.html.
Depending on the type you have, make sure that the float switch is not stuck.
Sounds like your float is stuck