In my HW296 I remove a panel near the water heater (locate water heater on outside and look inside at same location) there are two knobs, if at right angle to the tube, that is off, if parallel to tube is on. You can see the tube that bypasses the water heater and if it is on, and the other is off, that is why you have no hot water. then. Turn each knob 90 degrees to close the bypass and let water enter and exit the water heater. Is the anode tube on the heater in good shape?
2008 Forest River Rockwood HW296
2013 Ford F-150 Limited