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Does oil sitting in my above ground 275 tank turn to sludge?

Joseph_4 Member Posts: 274

 I have oil, live in nyc and want to switch to gas. but would like to leave oil tank in case gas shoots up and oil becomes cheaper (hey-anything can happen right?)

was told oil sitting in tank will turn to sludge and or decompose and cause problems.

during the 5 summer months only a little oil is used each day to heat my domestic water. I have a tankless coil. its been that way for the 11 years i own my house and i never heard this would cause problem. or is it because of that little movement in tank during summer months is enough to protect it?




  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    I'll take a crack at it.

    I'm not a chemical engineer, just an oil guy.  Heating oil today is not like the heating oil of yore.  It's more complex, and made up of many chemicals.  As the oil sits, these chemicals start to break down and separate (depolymerzation).  Also, if you tank isn't completely full, condensation will form, as well as microbes, forming sludge.  These microbes start eating at the steel in your tank. Use up all your oil, or pump it out.  Although you'll be charged to pump it out, many companies will buy this oil and use it in their waste oil heater.  If you want to use this oil after a few years, you're going to have to chemical treat the oil.

    Also, why would you want the liability of having an oil tank in your basement or yard?  When you change over to gas, if your installation requires any inspections, I'm pretty sure they're going to make you pull the tank.  Plus the tank could eventually fail, and maybe your insurance company might have a problem with you storing heating oil and not needing it.  If you switch back to oil, you'd be better off with a newer double wall tank.

    So the short answer, I'd get rid of it.  It will always cause you problems to store then re-use it.  I don't think oil would be cheap enough to switch from oil to gas to back to oil, and make it cost effective.

    There was an error rendering this rich post.

  • Steamhead
    Steamhead Member Posts: 16,889
    You never know

    which fuel will be cheaper per BTU five years from now. Five years ago, oil was cheaper.

    I'd still pull the tank. But if you use a wet-base boiler with a power gas burner, you'll be able to switch to oil without buying a new boiler. In that case, you'd get a new double-wall tank.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
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