[Dakota773]

I'd also look out for "crud / lime " being created by the boiled - hot water. I have one in my home and have replaced it 3 time because of water quality issues.  Most units are like a regular water heater but with a small 1 qt or so tank and a larger heating element.  If you leave them on they will continue to create 190' water and boil off a little every time they heat.  Typical water heaters are generally set to the 120' or so range, so you can see how different these are.  For all the effort (wiring, holes in counters, added water connections, etc.) it would seem just as easy and probably better in the long run to replace the water heater.