I have an 11 yr old 600 ft submersible well/pump system. It has a grundfos cu301 controller and well head says "Monitor", but that's all I know about it. Seems to have worked flawlessly for the last 8 yrs. I recently noticed that my electric bills have been 30% higher than last year, and traced the consumption to the pump breaker. Close it, and the meter wheel spins fast, even when using no water. Open it, and the house power consumption goes to almost zero. Could something have "short circuited" on the water flow side, making the pump work full time?

Verification or any other ideas would be appreciated,