Just bought a 2011 Thor four winds chateau 21c. We took it to a campground close to home, plugged it up and connected water and went home to get the boat maybe hour and a half got back to the camper and a hissing sound was coming from behind the frig. I was on the phone trying to find out what it was and started smelling ammonia then sizzling sound came from top vent of the frig and smoke come out the vent I unplugged the electricity. What has happened.