Have RV Questions? Ask an RV Mechanic Online.
Any chance that the bypass valve(s) are in the winterizing position(s) here? That is the usual cause. Check that and get back to me and we can dig deeper if need be. All follow ups are included in our fee.
There is no "mixing valve" on this model............and I am adding a link to the Atwood Water Heater manual for you. Print out a copy as there is a lot of great information in there about operation and trouble shooting. http://bryantrv.com/docs2/docs/atwoodwaterheater.pdf