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How to know its time to think about replacing a gas hot water heater...

edsut Member Posts: 19
I moved into a different house about 6 months back... I've already used this forum for a few questions... Great forum, and thanks in advance...
The paperwork from my home inspection said that my water heater is over 20 years old. I found nothing on the water heater that indicates its age (AO SMITH PROMAX), so I posted a [yet-unanswered] question to AOSMITH giving them model/sn to see if they can tell me the age.
Anyway, it works just fine, but if it actually is >20yrs old, my guess is "any day now" I'm gonna be out of hot water. It does make some odd noises when hot water is being drawn from the system, but other than that it seems fine.
How do I know its time to be ahead of the emergency and just replace the thing?


  • psb75
    psb75 Member Posts: 384
    If its 'rumbling or popping" when heating water, it probably needs to be emptied and de-limed. After that your good to go until 1.) the tank starts leaking or 2.) the burner goes out. Enjoy the hot water until then.
  • Jamie Hall
    Jamie Hall Member Posts: 16,063
    Sadly, you don't. The odd noises which you hear most likely mean that it could use draining and flushing and no more than that.

    If it has an anode rod, it probably wouldn't hurt to replace that if you can.

    Otherwise... the most usual failure for a gas or oil hot water heater is a leak, usually around the base somewhere, which you will notice as a sad little puddle or damp spot. This tells you to get the thing replaced as soon as you reasonably can, but not to fly into a panic. While catastrophic failures can and do occur, they are mostly related to a failure of the pressure relief valve and overheating.

    On the other hand, if it's electric (the Promax can be either) they can and do fail without any warning at all when one element fails. That, however, is something which usually can be repaired quite easily and cheaply, and only leaves you with the nuisance for no hot water for a bit.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Big Ed_4
    Big Ed_4 Member Posts: 1,732
    Rust and corrosion along the seam of the bottom base is a good tell tail ....
    I have enough experience to know , that I dont know it all
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,198
    Hi, I like to check in the combustion chamber first if there is one, and see if there is any dampness or heavy rust. Then look at all fitting penetrations in the tank. Look for rust on the jacket and try to determine where it came from. If all that looks okay, pull the anode rod. If you get just a plug, not so good, but do install a magnesium rod anyway. I’ve gotten many more years from tanks that had no anode left. If the tank leaks anyway, save the rod for the next tank.

    Yours, Larry

    Ps, best to turn off the water before pulling the anode :o
    EBEBRATT-Ed Member Posts: 9,176
    All good advise above. AO Smith can certainly pinpoint the age. It's usually on the tank though
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