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Copper oil supply lines: what are those loops?

seized123 Member Posts: 290
In photos I see nice circular loops in copper supply lines to the burner. I don't have those on mine, but I do have flat-laying loops above the tank.

Any purpose to these besides extra tubing in case of alterations/ repairs?

For my new upgraded one-pipe supply line, should I make sure there are loops both inside and out? If so, does it matter where the inside ones go (before/after filter, for example, or whatever)?

And how do you make those things - tube bender I guess combining 180 degree bends ...


  • pecmsg
    pecmsg Member Posts: 4,390
    edited July 29
    Movement. Expansion contraction. 
    less stress when it has to be moved out of the way for service. 

    For a larger loops, by hand or my B Tank. 
    All others a bender prevents kinks
  • Jamie Hall
    Jamie Hall Member Posts: 22,175
    Mostly for expansion and contraction and flexibility to make connections or take them apart -- loops are nice and neat, but so long as the pipe has wiggles in it, not a big deal.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • seized123
    seized123 Member Posts: 290
    Okay, so mostly the idea is to have lots of extra tubing in some form, loop or not, thanks!

    pecmsg, what’s a “B Tank”? Like an acetylene tank you just use to just wrap the tubing around and make nice circles?
  • Big Ed_4
    Big Ed_4 Member Posts: 2,541
    Years back before the tiger loop there was a time that we added loops , in theory it was a form of a check valve . It did not work :) The upside down filter was another....
    I have enough experience to know , that I dont know it all
    EBEBRATT-Ed Member Posts: 14,560
    Have loops or not it's just for extra tubing the amount of expansion is nothing to consider.

    Wrap the tubing around a coffee can or something if you want
  • MikeAmann
    MikeAmann Member Posts: 910
    Ed beat me - coffee can, peanut can, etc.
  • mattmia2
    mattmia2 Member Posts: 8,889
    It helps isolate the vibration from the burner and other equipment from the lines attached to the structure somewhat too.
  • Big Ed_4
    Big Ed_4 Member Posts: 2,541
    Tank hum , it brings me back...
    I have enough experience to know , that I dont know it all
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 6,761
    edited August 2
    I remember the first time I added a loop to a oil tank in 1974 or 1975. The old model J pump had a small plastic air cushion wafer in the pump to reduce the gear set hum from traveling back to the tank which acted as an amplifier. Of course, while doing oil burner tune ups, we would always remove the 8 bolt cover and either clean or replace the strainer. Once in a while, you would find one of those wafers in the clean-out Jiffy-Juice bucket when you were done. OOPS, oh well... too late now! and off the the next call. Most of the time there was no problem anyway.

    But the office got a call from a customer about this strange noise coming from the tank. The records show that I just completed the tune up the week before. The service manager took me aside and explained "Tank HUM" and how to fix it with a coil of copper tubing. It stops the harmonic path of the vibration from the pump the the tank.

    I was given the task of returning to fix my screw up the next day. When I arrived, I explained the problem to the customer and how it can just crop up after years of quiet operation. But that when I found out yesterday, I was going back to fix it. I thought about it all night and what could possibly cause this noise, and looked it up in my old trade school textbook. That is where the old timers found out about the coil of tubing would fix it.

    I added a 2 loop coil at the tank with a flare union and Viola! The noise was gone. Two days later that customer called the office to thank me for the extra effort I made on his behalf. The boss keeps all those complement and complaint cards on all the employees.

    Every time there is an employee review, those cards come out. Once I knew this, every time a customer would complement me on a job well done... I would tell them, "you really think so? You know, My Uncle Frank was having a particularly bad day when I left to shop this morning. If you would just call the girls that answer the phones in the office, and tell them what you just told me, that would make his day!" I had the record for complements from customers. My stack of complaint cards was about 1-1/2" tall while the complement stack was over 6" tall. Uncle Frank said I was the only service tech in the company that had more complements than complaints. Go Figure!!

    We didn't have social media back in the day, but it never hurts to ask for a good review today, I like the "Boss is having a bad day" approach, it gives the customer a little more incentive!

    Mr Ed.

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics