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Suntec By pass plug

Bill Julian
Bill Julian Member Posts: 120
I recently installed a GO-5 beckett oil burner/new boiler but the system existing has a 2 pipe line. I hooked the existing bypass oil line but without the plug. (I do mostly gas).
What is the ramifications of not installing the bypass plug. Its only been 1 day since install. I have the plug now in hand.


  • Steamhead
    Steamhead Member Posts: 15,329
    The burner may not be able to pump the oil. This problem may not show up right away however.

    If that were my job, and the usual single-line hookup would not work, I'd use a TigerLoop to eliminate the return line. Return lines run under some pressure, and can cause much environmental damage if they leak.

    You would need the bypass plug to make the TigerLoop work.


    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,687
    edited June 20
    Are you sure you need two pipe?
    If it’s the same model fuel pump as the one you took out, you could reuse the plug from that one.

    Note to anyone who stumbles onto this thread.
    If you did it the other way, put in a bypass plug and switched it to one pipe oil line, you would almost instantly destroy the fuel pump.
  • Bill Julian
    Bill Julian Member Posts: 120
    I have a tiger loop there. Im going over today and installing the plug and keeping the 2 pipe system.
  • harveysa801
    harveysa801 Member Posts: 1
    The SUNTEC AN oil pump is the basic model incorporating a pressure regulating valve with cut-off.
    The gear set draws oil from the tank through the built-in filter and transfers it to the valve that regulates the oil pressure to the nozzle line.
    All oil which does not go through the nozzle line will be by-passed through the valve back to the return line, in a two pipe installation or, if it is a one-pipe installation, back to the suction port in the gear-set; in that case, the by-pass plug must be removed from the return port, and the return port sealed by steel plug and washer.
    The valve also has a cut-off function as follows:
    During starting period when the gear-set speed is increasing, all the oil passes through a special flat on the piston, back to the return. Once the speed reaches a certain value and the flow can no longer pass through this flat, then the pressure increases rapidly overcoming the valve spring force and opens the valve.
    During the stop sequence, the gear-set speed slows down and the valve closes when the gear-set capacity is lower than the flat flow.
    The cut-on and cut-off speeds depend on the gear-set size, and set pressure.