If your water heater still works with propane (check it), you can rule out the thermal protection fuse. Otherwise, I don't believe there is a specific reset button to push. Try checking in the fuse panel on your converter charger for the water heater 12v fuse on the lower section and doing a reset of the 110v water heater switch above.
Please give us an update, thanks.
2004 Winnebago Minnie 22e(went to a nice family Oct 3, 2015)
2016 Forester 2701DS (Aug 31, 2015)
2015 Camping 3 trips 6 nights
2016 Camping 9 trips 28 nights