This is a 2017 Newmar Dutch Star that has lost its hot water. Burner is on and boiler is up to temp. What do you do next? The oasis DM12 relies on circulation pumps to circulate boiler fluid through a heat exchanger which in turn heats the water. You can isolate the issue pretty easy without going into extensive troubleshooting. Turn on your thermostat to see if it changes the water temperature, if it does your summer loop pump may be out. The reason being zone 1 and 2 pumps circulate through the heat exchanger to heat the water in addition to the summer loop pump. When the zones are off is when the summer loop pump kicks in to circulate through boiler fluid through the heat exchanger to make that water hot, so if the pump has failed and is not operating you won’t have hot water. You can watch a video here of how I troubleshoot this situation. This test has to be done with the water on at the tap during testing. This is a common failure and fairly quick fix.