On Mon, 18 Feb 2008 18:00:09 -0700, Bob M. wrote:
I remember from boats that the sacrificial anode needs a good solid ground
connection to the engine or transmission block.
Yes, and it is even with a layer of teflon tape. Can be easily tested with
a meter. If someone's really concerned, use anti-seize compound available
at auto parts places. It's used for spark plugs.

I think "grounded" might not be the right word; but the anode must be
"connected" electrically to the tank as a requirement for its purpose.

I do remember in my research last week (oh so long ago) one article where
guys tested it with an ohmmeter and found that Teflon tape didn't hurt the
anodic action.

Here's one article that says distinctly to use Teflon on the anode:
http://www.inspectorsjournal.com/for...?TOPIC_ID=2431

There it says:
"Remove the old anode rod with a 1 and 1/16 inch six-sided wrench or
socket. Do NOT use a 12-point wrench or socket or you will strip the head
of the anode. Get at least a 24-inch cheater bar. I keep a piece of 3/4
inch black iron pipe in the garage just for this purpose. Place the cheater
pipe over the socket handle. Have someone hold the water heater while you
slowly break the seal. Once broken, the anode removes quite easily."

It goes on to talk about the Teflon:
"Replace with a new anode rod. It is a 3/4-inch National Pipe Thread (NPT)
part. You may find one at any plumbing house or home store. Use pipe sealer
or Teflon tape to seal the threads. Snug it down tightly. Remember the
water heater builds up 150 PSI of pressure inside the tank."

BTW, where does the 150 psi come from?
I thought incoming water was about 80 psi.
Does just the fact we're heating the water raise the pressure?
Why? It's only 120 degrees (merely hot); not 212 degrees (boiling).

Does the pressure of the hot water rise to 120 psi while the pressure of
the cold water remains at 80 psi?