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Have a 50 Gal back up Propane water heater, How Do I store when not useing it? Worried about bacteri

JoeG Member Posts: 88
Have a 50 Gal back up Propane water heater, How Do I store when not useing it? Worried about bacteria.

I have a AO SMITH 50 Gal Propane Hot water heater that I plumbed in as a back up in case my Navien On Demand goes down. 

Should I Drain it? 

With water in and out shut off?

I dont plan On using unless needed I am going to shut gas off to it. I

have it running right now With the hot out shut off just to make sure

it works and I have heat control all the way up would like to kill any


Should I put bleach in it and leave it fool with in and out vavles shut?

There was a few little bug looking like things in it when I flushed. it

sat openfor a little while and the anode rod slugged up the bottom, I

changed teh aluminum for a magesisum one.

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  • Larry Weingarten
    Larry Weingarten Member Posts: 3,335
    If you don't know how long...

    ... the heater will go unused, I'd flush out sediment and do everything I could to dry the tank inside so no rust could happen as it sits. 

    Yours,  Larry
  • JoeG
    JoeG Member Posts: 88

    How do you dry the tank out? I put teh new anode rod in which was 42 Inch I didnt cut it down, The one that came out was 29 Inch.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Drying it out....

    Pull the hot water outlet pipe out, and insert a piece of 1/2" PEX and connect that to a water vacuum, and lower the PEX to the very bottom, and suck the residual water and sludge out.

    If you can't do that, drain the tank as well as you can, and leave it open to the air. It will dry itself out over time.

    As for series it with the tankless, I would not recommend it, especially in light of your discovery of "bugs" in the water. Legionella and Pontiac fever bugs are omnipresent, and given the right conditions, will flourish and multiply and cause health problems. With the tank in series, and no means of circulation, you would have to maintain a high (130+) temperature in order to remain some what bug less.

    Been there, caught that (Legionaires disease) and almost died from it.


    There was an error rendering this rich post.

  • JoeG
    JoeG Member Posts: 88

    I have the hot water cranked all teh way up, will that kill the bugs?  Should I use bleach and let that sit in there after I drain it?
  • JoeG
    JoeG Member Posts: 88
    Hot Hot

    If I crank it all the way up how hot will the water be?
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    how hot will the water be?

    I read a report from a Canadian health agency that said you would have to heat the water to over 140F to kill most of legionella bacteria. On the other hand, Johns Hopkins report that 140F water will cause First Degree burns in 2 seconds, and Second or Third degree in 5 seconds. So you sure do not want to supply that to the users. There are a lot of studies and they do not agree. This study seems well done, but most people may not have the patience to read it.


    I have a Weil-McLain indirect fired hot water heater. It has a dial on top, calibrated in arbitrary units. It has an arrow pointing to one division and they suggest using that as a starting point. I did. It was so hot it went off the top of the dial on my thermometer (125F) and must have been 140F or more.  They say that heater is not rated for over 160F, but they recommend a supply of 190F, so It could certainly get that high. The boiler controls will keep the supply under 20F if they are working.
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