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high vacuum advice tiger loop 2 stage pump

captainjdog Member Posts: 2
Been troubleshooting a boiler for a few months, but i think I finally have it narrowed down. The pump is 11 feet above the tank and a run of about 20 feet. Its a 2 pipe system with a single stage suntec pump. Just ran new 3/8s lines & new filters (2 inline). Its currently pulling 13 in. hg vacuum. The system fails at 18 in hg which takes about a month. It doesnt take long and I'm always nervous I will come home to a frozen house.

I can't figure out a way to lower the vacuum any more so I ordered a 2 stage pump because 13.in hg - 18 in. hg is too high for the single stage. Apparently 2 stage is good for 17 in hg. vacuum.

Do you think this system is a prime candidate for a tiger loop?

Or would a booster pump work better?

I have zero experience with either.

My goal is to reduce the required maintence on the system and improve reliability. My thoughts are a tiger loop would extend filter service and reduce vacuum on the pump. Im not sure if anyone can chime in on the reduced vacuum using a tiger loop. I would think I still can't get around the 11in hg required to lift the oil 11 feet.

Any advice before I head down this road?



  • 776v63
    776v63 Member Posts: 61
    Webster Service Tech Handbook.

    Relevant information starts around page six.


    Seems to indicate a 2 stage would be better. Possibly larger oil line also.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    edited January 2016
    This is a perfect candidate for the Loop, I've done overhead shop furnaces with this exact scenario with total success. I would do either the Tiger Ultra with integral spin on filter and hg gauge or 1 spin on filter at tank. The extra filter adds unnecessary restriction- something you don't need. I would put on the 2 stage pump, 3/8" ID line would be better if doable, otherwise see how it pulls with the 1/4".

    I've got systems running like this for almost 25 years.
  • captainjdog
    captainjdog Member Posts: 2
    Thanks for the response Bob, and for the information 776v63.

    I'll post my successful results :)
  • spoon22
    spoon22 Member Posts: 32
    Tigerloop is the way to go by only pulling 1 pipe you will only pull the firing rate of furnace through the line which will drop the vaccum .