And, a tip on changing them over, as there seems to be some confusion on the matter...
Bushtracker sez....A couple of things that may help you....
First of all, it is not harshness of the water that accounts for the life of the Anode, as it seems that many think, evidenced in a previous Posting Thread. Maybe I should explain why the differing life spans of the anode and why it cannot be predetermined and should get an annual inspection...
This is a sacrificial anode in terms of Anode and Cathode... And in this case we are combating electrolytic corrosion.... In other words, when you are on a poor power supply and there is a bit of stray current around, what actually happens is a bit of electrolysis of dissimilar metals.... And without getting too carried away with Chemistry and Physics, the less "Noble" of the metals on the "Periodic Tables" of "The Elements", will donate metal to the more "Noble" of the metals.... This stray current that carries the process from the Anode ( the Donor) to the Cathode ( the Recipient) is what we are battling with the Anode. The Anode is sacrificed instead of metal inside your water heater... This amount of stray current and how clean your power supply is on the Neutral and Ground, or if you have any appliances leaking a bit of stray current onto the neutral or ground, will determine the life span of your Anode.... Harshness or hardness of water may deposit some calcium on the Anode, but only if it is not being worked by the process of electrolysis... It should just be eaten away, as minor salts in the water supply conduct stray current which picks up the metal off the Anode and deposits it somewhere else... In the case of the zinc it will pretty much flake off of where it is deposited in time.... This same process I have described is a microcosm of what is done in the "Electro-Plating" process that most would be familiar with...
On the process of changing it, just use a bit of Teflon pipe dope, and it will easily come out next time for an annual inspection.... Do not overtighten it, nice and snug, fill the threads with white Teflon pipe dope, and no problem next time....
Leave the pumps off when you do the process, and water heater cold of course...
And have the replacement ready to go, and you pull one out and put the other back in without wasting water... 50% gone is still a good anode... Much less, say 25% of new and I would replace it, they are not very expensive... About $25 from memory, and can save the tank on the HWS...
Cheers from the "Lone Ranger" at
Bushtracker
Cheers from the "Lone Ranger"