Hey guys, Atwood makes sensors with different temp settings, plus the adjustable (no experience with it); the typical is set to 140. Be aware the re-fire range is set to call for heat once there is a 20 degree drop before heat is activated again. If you go cooler, say one set for 130, it reheats at 110. The lower you set the temp, the faster your supply gets depleted as you use less cold water in the mix!
I don't have the adjustable, but have heard those sensors may have a shorter life span from those to whom I've spoken: totally unscientific for sure but the forum loves opinions so why not propagate it.
Insight - If you change out the sensor, be sure to put thermal grease between the tank and the sensor head to ensure the most accurate temperature reading. If you changed sensors without doing this, the heat loss between irregular surfaces can cause the tank to hold water much hotter than the 140 setting.