On Sat, 8 Aug 2015 10:28:16 -0400, "Robert Green"
wrote:

"Ashton Crusher" wrote in message

stuff snipped

speaking of muck, I've had far far less muck form by turning the
temperature down below "normal" on the dial. I keep it around 120
degrees or less and it seems to reduce the formation of muck and crud.
When I used to run them hot they would build up muck all the way up to
teh bottom element (and make it burn out) in only a few years. I
almost couldn't get one of the elements out it was so encased in
calcium buildup.

I haven't taken mine apart but it's outlived its predecessor which used to
run at 140F (I keep mine at 120F coming out of the tap - eventually - but it
takes a while to get there.) We'll see when this one dies. I also trimmed
the cold water input to the tank to try to limit the thermal shock of 36F
water (the lowest I've ever measured) hitting 120F internals.

What I haven't come across yet (still looking) is something on the web that
explains how water heaters build up so much sediment. The "duh" answer is
of course, sedimentation but it seems to be more complex than that otherwise
there would be sediment filtration on the incoming cold water line.

You would also think that heating the water causes more sediment to dissolve
so I am not sure exactly what most causes gunk buildup. I suspect it's the
quality of the water, but I haven't seen any study that apportions the
causes of sedimentation.

Yes, you would think heating it would make it dissolve stuff, not
precipitate it but perhaps the fact that it just sits there perking
away (figuratively) much of the day with no water movement somehow
results in precipitates dropping out. Or perhaps the mixing of cold
and hot water causes precipitation regardless of it being on average
quite hot and lessening the high temp results in less of that presumed
effect.