Went to a no heat call. Nothing was working when I got their. Took the fuse out put a 3amp popper in system worked just fine. Refrigerant levels where good and all low voltage wiring indoor and outdoor look fine. Also, the emergency heat was working as well. I could not find a reason for the fuse to pop. I left the popper in so if the issue happens again the home owner can reset it until we can come back and fix the issue. M#ARUF37C14AC s#1807304934