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Sharing Oil lines

Servicewiz_3
Servicewiz_3 Member Posts: 64
in Oil Heating

Many years ago I had a problem with a Boiler & Water heater sharing oil lines.

The resolution was a piping diagram , that showed a piping configuration that

resolved the affect , one oil pump had on the other. Would someone be able

to recall this piping diagram? thanks in advance for any help!!

Comments

  • HVACNUT
    HVACNUT Member Posts: 6,744

    1 pipe or 2 pipe?

    I do remember something but I don't feel right printing it because I'm not 100% sure I remember it correctly. And even if it is correct, it's not correct.

    That being said, if 2 burners are fighting each other for fuel, there's only one real solution. Repair/replace the oil line(s). The easy out is a priority relay on one burner. Usually the water heater. But that's not really fixing anything. I

    techforlife
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,703

    You can only share oil suction lines if the oil is gravity feed from the oil tank. One burner will fight the other burner for oil if there is any lift involved and No…. check valves will not fix it.

    If you have a lift situation each burner must have its own suction line. Burners can share a common return line to the tank if it is a two pipe system.

    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 10,399

    This is an interesting diagram from the Webster fuel pump folks from a time gone bye

    Screenshot 2025-04-30 at 10.27.25 PM.png

    The tank that is below the burners is showing 2 check valves (one at each burner). Less than ideal because we don't like to see check valves on fuel lines, but if Webster says you can do it that way in a pinch, then it is good enough for me.

    Best way is to use separate draw piping from the tank whenever possible.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,703

    two burners on one suction line with lift is very questionable. never had that work reliably.

    If I was going to try that (and I wouldn't) I would have one burner on priority (the hot water and not allow the burners to run at the same time.

    Two identical oil pumps never pump the same and the fittings and pipe length are never the same. That means both pumps will have a different vacuum and fitting resistance.

    Run them together and one burner will steal oil from the other.

    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 10,399
    edited May 2

    As it says in the illustration #3 Only used this as a last resort when it is impossible to use a separate suction line to the water heater. And I like the priority idea, I have done that before when the venting system isn't large enough. So It would be a great idea for this particular fuel line situation.

    I can provide the wiring diagram if needed.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

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