A friend of mine gave me an incubator and some fertile eggs, but the incubators temperature and humidity keep on changing. It will not stay at the temperature i set it at. I set it at 37.8 °C (recommended as it tends to get too low, same with humidity) and humidity at 70% and i keep having to reset it because it wont stay. Its constantly going either up or down(both temperature and humidity) and i cant keep it stable. Why is it doing this and how do i stop it? Pretty sure its a generic one not a specific brand.