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Dual Oil Tank

Ghost08 Member Posts: 1
I am installing two oil tanks in my garage and I would like a schematic for a two-tank hook up, outside fill, with 1 supply and return line for both tanks (but separate lines). I'm attaching the schematic I've been using as my guide, but now have been told it's faulty.  Thoughts/suggestions?  Thanks in advance.


  • billtwocase
    billtwocase Member Posts: 2,385
    There is a lot wrong with that pic

    First is the vent pipe diameter should never be smaller than than the fill. Common sense, and code here in Mass. I would also consider separate fills, and vents. Also any thermal valves codes where you are? Also be mindful on keeping them the same height. 
  • Big Ed_4
    Big Ed_4 Member Posts: 2,055
    edited December 2010

    Throw away that old diagram out, it must have come out of a 1930s handbook when oil was just starting to replace coal ... Twin tanks need an equalizing line between the two tanks which is a 1/2" line connecting the two bottom tank valves... Between the two tanks along the equalizing line you can tap off a supply into a filter first then branch to two separate lines .. The tanks need to be pitched down toward the valves ... Single fill and vent set up would be ... A two inch fill line piped into the first tank , this would be the pressurized tank , from the pressurized tank pipe a two inch pipe to the second tank which we call the vented tank .. On the vented tank you would add a tank whistle not to be cut if using horizontal twin tanks .f From the whistle pipe the vent out side . All fill and vent lines need to be pitched down toward the tank . And you can only use one tank gauge on the vented tank only .. As posted you need to check local codes
    I have enough experience to know , that I dont know it all
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