Trane XE 1000 Blowing fuse

[KTM450EXC]

I have a heating system with a heat pump that keeps blowing the 5AMP fuse when it works harder calling for heat. Generally speaking, the fuse will blow when the system has a 5 degree difference in temp ( working harder). But if there is only a small difference in temp, (say 2-3 degrees) it doesn't blow the fuse and heats fine. Any ideas would be greatly appreciated.