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Oil Line Sizing

is the tank outdoors? Not a good idea to pull two units from one line, and Never use check valves on oil lines.How far is run(s), do you really need that return line,maybe that opening could became supply too.


  • BrianK
    BrianK Member Posts: 4
    Oil line sizing

    Does anyone know if I can connect a new boiler oil line to the existing 3/8 oil line from a tank after the valve. The new boiler is an MPO147 1.05 GPH and the existing furnace is .85 GPH. I will be removing the furnace eventually and installing a hydroaire system. The tank only has one plug on top and a oil fired water heater with a two pipe system is connected there. If I can connect it do I need check valves on each line so I don't pull from each other.

    Thanks for your help.
  • ray hickethier
    ray hickethier Member Posts: 26

    YES! You can run two appliances off of ONE oil line! Just be sure to blow out the oil line if it`s been in awhile to be assured that the 3/8 diameter is complete and not restricted. Do NOT use compression fittings! Flare only! The worse case scenario is adding a priority relay so only one appliance runs at a time.
  • Brian K_2
    Brian K_2 Member Posts: 3
    oil line sizing

    The tank is inside. The distance to the boiler is about 20 feet. The other unit is about 10 feet. The furnace will be removed in a few months so it should only be temporary. The water heater burner (Carlin I beleive) said to use a two pipe system if there is any lift so I do not want to remove the second line.
  • Bob Harper
    Bob Harper Member Posts: 1,034
    other reasons to replace oil lines

    Is this line damaged? Properly supported and protected? Marked?

    I think it would be well worth it to replace it with 1/2" copper coated with red PVC and labeled for oil. Also, add a Tiger Loop with a Gar-Ber spin on secondary filter for that small nozzle. Cheap insurance. Did they report sludge or some other reason for the 2 pipe?
  • ray hickethier
    ray hickethier Member Posts: 26

    you do NOT need to make it two pipe! If it is an indoor tank and you are drawing off the top the lift is not enough to affect it. Also the new oil line and tiger loop and Garber filter should be done AFTER the heater is eliminated and you are using only the HWH in my opinion.
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