Control panel, no power

[Notanlines]

Last evening we came home to no hot water. 20 amp fuse for the water pump and control panel was blown. I replaced the fuse, water heater worked, we went to bed. This morning fuse is blown again. Never had problems with this situation previously. Any good ideas? Any most obvious I might be overlooking?
No water heater on propane either, no water pump, tank sensors aren't working, power control system panel not lighting up.

[Notanlines]

Many thanks to all and the suggestions and offers. We have a happy ending. The repairman with a little help from me, ran it down to the exterior step light which was also wired into the same fuse. It is all buttoned up, secure, and everything works. Well, the next owner will have to install their own step light.