You may be better off running a new hot wire instead of using the jumper. It is a lot easier to keep everything sorted out and if the switch is before the controller, it will keep the controller always on.
If you wire it that way, you would just run a hot and neutral to the power terminal and then connect the two wires that were on the mechanical aquastat to the NO and C connections on the other terminal strip.
You can use a jumper if you know the hot wire and not the load wire is jumpered to the 120v terminal.
Anyway, if you put all the wires in the same terminals as the Ranco (by terminal label) then it should have been wired ok. Did you take a picture of the connections? If you could post that and tell us what each wire is, we can tell you for sure if anything was wrong or if it was just a bad controller.
The only thing I can think of that would have caused what happened is if you had a neutral wire and a hot wire both connected to the relay terminal strip and once you changed the setting it either energized or de-energized the relay and shorted out.