I had to replace the heater element on my LSM 95-Sprint-E and did a quick inspection for scale while I had the element removed. No scale. But, at the bottom of the tank there was maybe 1/4" of a gray/white sludge - a lot like baking soda. I rinsed the boiler out thoroughly and it is now perfectly clean on the inside.

But, does someone here know what that sludge is? And, is there something I can do to prevent it from collecting again?

BTW, the machine is 8 years old and has always been plumbed through a softener and filter which are changed 2 times a year. This is the first time I have ever had the boiler open.

Minerals precipitated out of the water. Flush the boiler more regularly to prevent recurrence.

Thanks. I'm sure that's what it was.