I have a payne HEAT PUMP model# PH10JA048-B. It stopped working last night. I noticed the breaker was tripped. When i went to turn it back on it wouldn't allow me and kept tripping. I checked the disconnect and the whip to the heat pump and it all checked out fine; when i reconnected the whip back to the heat pump it tripped. What could be the problem that would trip the power to the unit? It was installed 8 years ago and the only thing i have had to replace since install has been the capacitor.