On Sat, 07 Nov 2009 21:38:02 -0500, tnom wrote:
There is some debate about whether or not the feature is
effective at reducing sediment.

Yes, it works. Just checked mine after 10 years.
No sediment came out of the drain.

That sounds like mine (not self-cleaning). Sediment was there, but no
sediment came out of the drain because the drain valve's water pathway
is too small and angular to allow the sediment to come out. :-)

(it seemed to be about 1/4" x 1/4" in places - so all it takes is for a
flake of scale larger than that to fall to the bottom of the tank, and
nothing will escape the drain valve except water - giving the impression
that there's no sediment in there)