On Wed, 21 Oct 2009 09:33:25 -0700, hr(bob) wrote:
It's a gas heater

yes, duh, sorry about that. That'll teach me not to post when I haven't
had enough coffee

I think I'll just wait 2 or 3 years and try again. I didn't
see any small particles or anything, just clear water coming out the end
of the hose I was using to drain it so maybe our water is pretty good.

Fairy nuff. If there's no apparent problem then it makes sense, I suppose.
If it's partially silted it'll lose efficiency, but there's probably no
easy way to monitor that over time with a gas heater.

(I must have pulled about ten gallons of crud out of ours, which obviously
hadn't happened all at once - yet in terms of water temperature it had all
seemed to be working fine until recently, and previous checks of the water
from the drain valve had shown no signs of build-up because the poor valve
design wasn't letting it through. It had probably been using way more
power than it should for several years...)

cheers

Jules