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Benefits of 2-pipe vs single

Damon Member Posts: 32
For an in basement tank with a Becket AF roughly even with the bottom of the tank and 8ft from it with overhead lines running 8.5ft from the basement floor, what are the advantages and disadvantages of a 2 pipe vs a single pipe. I know the 2-pipe has a greater flow through the filter (which I don't think is a bad thing) and the 2-pipe is self priming but other than that I'm just curious.


  • billtwocase
    billtwocase Member Posts: 2,385
    shouldn't need

    a 2 pipe system for that. If you have no air leaks, flair fittings, and good clean filters, you will be OK. 2 pipe system moves too much oil, and has the potential for oil leaks. If you have problems, then install a tiger loop. I personally have never needed one to keep the fuel flowing, but others will strongly recommend one.
  • Damon
    Damon Member Posts: 32
    No problems

    System works fine with no problems. The installers said they put it that way due to the overhead lines and because it's self priming. All the other houses I have been in with similar tank to burner locations have been single pipe and the line was run on the floor since the tank and furnace share a common wall. Unless my line was trenched in it would be a trip hazard since my tank is on the outside wall and my furnace sits near the chimney which is in the middle of the house and not on an outside wall.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,253
    Old timers prefer the two pipe system

    My father would not allow me to run over head oil lines with out them being 2 pipe. I know the science Bill, I do not disagree with a single word you wrote. I also know Dad had to deal with some old oil pumps in his day. When things are done properly one pipe would work fine, when they are not and the customer is prone to running out of oil 2 pipe makes for quicker priming. I was also told to trench it if possible rather than run over head.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Alan R. Mercurio_3
    Alan R. Mercurio_3 Member Posts: 1,619
    edited February 2011
    Re: Benefits of 2-pipe vs single

    For what it’s worth my 2 cents is this. If you look at what fuel pump manufactures recommend.

    Two Line systems are commonly used in applications where you have a long run and/or high lift of fuel line.

    If those conditions do not exist then it would be my professional opinion that a single line is sufficient.

    Please keep in mind that with a two line set-up oil filters, strainers and nozzles may need to be replaced more frequently and if the oil Tank is located outside a two line set-up will only promote an accelerated amount of condensation leading to the growth of bacteria known as sludge.

    A tiger loop should only be used to overcome a long run and high lift and/or to condition the fuel from an outdoor tank. Any other use of this device would be considered a band aid and in MHO should be avoided!
    Your friend in the industry,

    Alan R. Mercurio

  • icesailor
    icesailor Member Posts: 7,265
    Benefits of a 2 pipe Vs Single

    If the issue is replacing a gravity line that went under the floor and now must me removed, go overhead. Don't go a two pipe. It is a waste of material and money. Use a Tigerloop and go overhead. If the tank is on the same floor level as the burner, and you go overhead, it is still a gravity tank once it is primed. THERE US NO SUCTION ON THE LINES ONCE PRIMED!!!! You can prime it off the the burner pump but it is a PITA. If you connect it as a two pipe, it will self prime. A TIGERLOOP IS A TWO PIPE PUMP!!! Once you turn it on, it creates vacuum to lift the oil up and over the height of the ceiling. Once it goes over and starts down, it is a syphon. It will then warm the oil for better combustion.

    A Tigerloop is not a mickey mouse band aid. It is a legitimate valuable tool for us to use.

  • Damon
    Damon Member Posts: 32
    Benefits of 2-pipe vs single

    Single pipe is nice since it draws off the bottom and pulls all the sludge and water out. How far does the pickup in a 2-pipe go down in the tank? After 14 years I was surprised how little sludge was in the bottom of my tank... zero water too. This would be too complicated but has anyone ever seen a 2-pipe with the pickup coming off the bottom tap like a single pipe?
  • Big Ed_4
    Big Ed_4 Member Posts: 2,239
    Overhead lines

    The problem with one pipe over head line is that it now is a siphon line ... One would need to get all the air out with a push pull pump .. If not you will get a call back .. After Oil deliveries , service and run outs , your back to square one .. The pump alone with priming will not keep the air out of a 3/8" line ... Maybe 1/4" line but we here in the US don't use ..

    Top feed lines I feed is not the best option either . The level below will collect water and that sulfuric acid sludge would be breed ... Pitch the tank toward the valve and pick up the suction groom the bottom tap . Place the filter at the tank and if you want to keep it one pipe overhead add a ball valve after the filter.. This would help out will air during service and oil deliveries ... Tank pitch , bottom feed and filter would be the answer using a two pipe system on that cleaning the tank problem . No water no sludge...Old side tap or back pitch tanks excluded ..

    Two pipe you always have the charged oil line . With a hole you will have a spill ..

    Tiger loops are great but what Allen stated the manufacture does not want the level of oil higher then the tiger loop ..I think the problem may be having the oil bleed through the unit and cause a spill ???? If correct .. why not mount the Tiger loop up high above the oil level ..
    I have enough experience to know , that I dont know it all
  • billtwocase
    billtwocase Member Posts: 2,385
    Charlie my friend

    That was old school thinking, and in some cases still a must. I value your opinion as always. Oil was so much cleaner back then, like kero. This stuff nowadays will clog filters in less than a year . As Alan has mentioned they will dirty quicker as 2 pipe systems, and vacuum will be higher as well. I have seen the cases where it is a must, but this case is borderline. I still like them trenched in also, but sometimes overhead is the only way out, especially with the new update law. Can you see bare ground out your way yet? You've had for share of snow this season
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,253
    No bare ground except where plowed

    front yard has 3 feet of snow that is rock hard ice even after the warm weather today. 
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Bill Julian
    Bill Julian Member Posts: 128
    I or 2 pipe oil

    I have a my boiler and oil tank 50 feet from each other the oil line is going in an attic and thus down into the tank. 1 or 2 pipe system??
  • Jamie Hall
    Jamie Hall Member Posts: 21,111
    Cedric I had an overhead

    line -- single -- about 30 feet.  It was an almighty pain to get primed when the oil company ran me out of oil (automatic delivery doesn't always mean they get there in time...).  When we put Cedric II in we trenched the oil line across the basement floor, as Charles has suggested, and it primes much more easily now!

    Of course, as Charles may recall, trenching that line in wasn't quite as simple as it looked as though it was going to be...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • icesailor
    icesailor Member Posts: 7,265
    edited April 2014

    Thinking of playing in the Earth Band with a 5" Banjo, Earth Guitar, or electric percussion is making my head ache, sympathetic ringing in my ears and the back of my neck sweat.

    I'd have installed a Tigerloop, like they do all over Europe.

    I'm starting to think that local/professional resistance to Tigerloops is more of that American Exceptionalism I hear about. What works well everywhere else, won't work here.

    A Tigerlooped single line primes like a 2-pipe. With absolutely no venting of the bleed screw.

    Like beer cooler boilers with Gianonni HX's and wall hung heaters from Europe. They only work over there. America is different.
  • heatpro02920
    heatpro02920 Member Posts: 991
    I do not run anything but...

    single line tiger loop systems.... No dual lines unless they are inground tanks and I haven't done one of them.... ever....