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Second oil tank

get out a tape measure --the new 1 is on longer legs but from the picture they don't look to be different


  • Michael_38
    Michael_38 Member Posts: 5
    Second Oil Tank

    Added second oil tank. Original tank (87) says on the plate its 275 gal but compared to the new one is it *quite* a bit smaller ?

    Anyhow, tanks are for this install
    hoping for one fill this season
  • Problems


    It appears that you have a 275 and a 300 (or maybe a 330) twinned.

    The real problem is that the two tanks are different heights. Given that they are connected together at the bottom and liquid will seek its common level, if you fill both of the tanks to the top the oil level will be above the top of the 275.

    I can not see the top of the 275; however it should have its own vent alarm gauge. Vent alarm gauges are never supposed to be exposed to liquid oil. They only should have air displaced from the tank passing through them. They are not leak proof if filled with oil.

    If the 275 has a vent alarm gauge like the one in the top of the larger tank, the vent alarm in the 275 will leak oil when you fill both tanks to the top.

    Also, the vent pipes should not be connected together at an elevation lower than the top of any fill pipe opening. If they are connected together, (at the proper elevation above the fill pipe opening)) then the outlet pipe should be at least on size larger than the largest individual vent pipe connected into to it.

    Ed Carey
  • Michael_38
    Michael_38 Member Posts: 5

    thanks ed, the grey tank says 275 and when i bought the black tank it said 275 on the plate. side by side the are obviously not the same size ? Both tanks have vent whistles, yes, i need to think...

    how about if i use the ball valve to isolate the smaller tank until the larger is say 1/2 full or vice-versa
  • Michael_38
    Michael_38 Member Posts: 5

    ohh, i am such a dub. 10" legs on the old on 12" on the new :( $#^T makes me want to puke...
  • Dave Belisle
    Dave Belisle Member Posts: 68

    As Ed said , the vent pipes per NFPA 31 can not be tied together until they are above the fills.

    So the best thing to do is vent each tank separately ........ Then you are good to go...

    Dave in NH
  • Norm Harvey
    Norm Harvey Member Posts: 684

    One other thing in addition to Ed's comments, With a filter on each tank before the equalizing line, the tanks will not level appropriately as the filters become full. I recommend the equalizing line be piped in at least half inch and before the filters. That way the tanks will level appropriately.

    That being said, the "level" will be skewed due to the different tank heights as Ed points out.

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  • ChasMan
    ChasMan Member Posts: 462

    One is US 275 and the other Inperial 275.
  • Brad White_202
    Brad White_202 Member Posts: 105

    one might be a double-wall tank as many areas now require. The actual net tanks would be about the same dimensions and of course, volume.
  • Alan R. Mercurio_3
    Alan R. Mercurio_3 Member Posts: 1,620

    Forgive me for being critical but it looks like the pipe dope used on the fittings is Teflon based? If so this could also cause trouble down the road. Just a friendly heads up.

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    Alan R. Mercurio

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