Howard, welcome to the forum. I don't know what you mean when you say your trailer is a "208". Is it a 2008 model year trailer? Is the water heater an Atwood brand? Does it work not work at all, or does it possibly heat on Propane, or shore power only? Have you checked the fuse to that circuit?
If it's an Atwood, you should be able to locate an owners manual either here, or by using an internet search.
- Jack