This is such a good forum for getting knowledge about everything (I'm serious). So I'm gona try this question here. I have a 2012 bumper pull camper. Just out of warranty naturally. At first everything worked great. Now this problem. Every faucet runs hot water only. Even the commode fills with hot water. You can turn the water heater off and when the water cools you will get only cool water from each faucet(naturally). I called the place I bought it as well as one other RV dealer and neither said they had ever heard of the problem. One did say he thought maybe it was a by-pass valve stuck open, but then just as quickly said he doubted that was the problem. Will the by-pass valve be on the water heater or somewhere in the lines? The water heater is almost impossible to get to. I think the trailer was built around it. Any one had something like this happen to them?