You can make the temperature more stable by changing pid parameters settings push set button and hold a couple of seconds and start changing the p settings, and the I settings and the d settings until you get what you want, I have p on 1. And I on 540. And d on 320. But when you change the number of each you have to press set to store the value this is a starting point to see what is happening and you can Google the pid model and get the instructions on how to change parameters