You mean you have a digital temp and humidity gauge not thermostat? thermostats control temp not just give a reading. Sometimes those things can be junk. It happens. If your mist was hitting the gauge it should have jumped up to close to 100% in a few minutes. it shouldn't hurt it. Iv left mine in new vivs for a few days while misting to get an idea of how it cycles and its just fine. return it for a new one. Don't bother with the analogue ones. Their junk.