On Sun, 12 Jan 2014 14:16:27 -0800 (PST), Newton
wrote:

Is there anything wrong or dangerous about my idea to supply cold water input to a gas Hot Water Heater via the drain opening? I would include a TEE and a boiler tap so as to permit future draining. Also would cap old unused inlet on top.

Reason for this is to mitigate damaged dip tube. I do not have headroom to replace dip tube. Heater is 75 Gal (very heavy) and I prefer not to have to tip it to permit insertion of the new dip tube.

Thank you.

How much headroom do you have?

I think 18 inches is easily enough, and now that the topic has come up,
I think my 10" would be enough. I'll just have to bend the dip tube a
little more. It is once clear plastic, now dirty everywhere

I had an A.O Smith water heater, and now I have a Sears WH. I think
it's made by AOSmith because it's the only one I could find that has the
input and output the same distance apart as the original. And the
owners' manuals were very similar with the same drawings and pictures,
iirc.

When I tore the first Sears one apart, I saved the dip tub and it's
pretty flexible. I have a big storage shelf hanging from the ceiling
above the WH so I only have about 10" head room and I think it would be
enough. Like Chris says, you put it in at an angle until in my case,
only 10" are left.

My dip tube goes to the bottom and then towards the permimeter, and then
bends to swirl the water around the bottom, which iirc is suppose to
pick up sediment** The last 2" are molded into a sort of nozzle. But
before you replace a diptube, if the replacment is not symmetric, find
out how yours is oriented, and mark the top of the tube so you can
orient it as intended. In my case that would mean not pointing the
open end to the center or the outside, but parallel to the outside so it
made the water swirl.

** (although that would clog screens too? Maybe the idea is to swirl
it around when it is still microscopic, so it exits with the hot water,
and it's too small to clog anything?? ) When I tore the second water
htr apart after 8 years (probably a mistake to replace it. Maybe only
electrical parts were bad and I got confused, or maybe the dip tube had
come off (there is damage at the top, but I might have made that during
destruction.) there were only about 2 or 3 tablespoons of sediment in
the bottom At the rate it was going, it would take 80 years before the
sediment reached the electric elements, which is bad with electric WH.
With gas it's different I guess because the flame is underneath. )

Actually my diptube was fine after 8 years, Is this what's bothering
you?
http://voices.yahoo.com/how-replace-...p-8819775.html

If your WH is made during the problem years and your worried about it
falling apart and clogging screens, it's not enough to feed the water
heater cold water, you have to remove the old dip tube too, don't you.

http://www.familyhandyman.com/plumbi...tubes/view-all
http://www.dummies.com/how-to/conten...-dip-tube.html

Despite what this says, mine is not 3 feet it's over 4.5 feet. and then
another 14" for the curly part at the bottom. It's almost as tall as
the water heater. For gas it would be shorter because the gas flame
takes up space underneath.