Yong Heng Operating Temperature Range (Farenheit)

The last time I used my young thing I noticed that my temperature gauge wasn't working I can tell you what I do as a constant check while I'm filling tanks is I feel the output water if it's just lukewarm I think you're good. Mine has never gotten above bath water temperature. And when I switch to fill another tank I always let the output water run until it's cool before I start feeling the second tank. I don't know if you have to that's just all I do it in mine has work now for 3 years I think