Yes, the bottom has a build up on it. We have hard, limestone water here & it looks like something that has been wet or exposed to moisture for awhile, with no water on the floor. Also, I failed to mention this eariler - when the cancel/drain button is pushed and I hear a click, I then hear what sounds like an "electrical" sound like something sizzling. I have not been able to see where it is coming from, nor is there any smoke or a smell.
Many thanks! What do I do now?