This is a great piece of "added insurance" to make sure that my heating/air system in my attic area doesn't malfunction and cause condensate to soak my ceiling. While this isn't a substitute for making sure the condensate drain line is checked periodically, it provides additional protection if the drain line gets plugged and if the drip pan starts to overflow. I checked this out with my ohmmeter when I got it, and the internal float switch works perfectly.