Find an example file that is specific to the object in question. In this example, FourPipeBeamLargeOffice.idf. Then search for the object. The notable connections in this object are the air and water node names.

Note that there are 2 air nodes, and 2 sets of water nodes. There are no coils in this object, they are inferred.

  AirTerminal:SingleDuct:ConstantVolume:FourPipeBeam,
    Core_bottom 4pipe Beam, !- Name
    HVACOperationSchd , !- Primary Air Availability Schedule Name
    HVACOperationSchd , !- Cooling Availability Schedule Name
    HVACOperationSchd , !- Heating Availability Schedule Name
    Core_bottom 4pipe Beam Inlet Node Name , !- Primary Air Inlet Node Name
    Core_bottom 4pipe Beam Outlet Node Name , !- Primary Air Outlet Node Name
    Core_bottom 4pipe Beam CW Inlet Node , !- Chilled Water Inlet Node Name
    Core_bottom 4pipe Beam CW Outlet Node , !- Chilled Water Outlet Node Name
    Core_bottom 4pipe Beam HW Inlet Node , !- Hot Water Inlet Node Name
    Core_bottom 4pipe Beam HW Outlet Node, !- Hot Water Outlet Node Name
    AUTOSIZE , !- Design Primary Air Volume Flow Rate
    AUTOSIZE , !- Design Chilled Water Volume Flow Rate
    AUTOSIZE , !- Design Hot Water Volume Flow Rate
    AUTOSIZE , !- Zone Total Beam Length
    0.036 , !- Rated Primary Air Flow Rate per Meter
    597 , !- Rated Beam Cooling Capacity per Meter
    10.0 , !- Rated Cooling Room Air Chilled Water Temperature Difference
    5.2E-5 , !- Rated Chilled Water Volume Flow Rate per Meter
    CapModFuncOfTempDiff, !- Beam Cooling Capacity Temperature Difference Modification Factor Curve or Table Name
    CoolCapModFuncOfSAFlow, !- Beam Cooling Capacity Air Flow Modification Factor Curve or Table Name
    CapModFuncOfWaterFlow, !- Beam Cooling Capacity Chilled Water Flow Modification Factor Curve or Table Name
    1548 , !- Rated Beam Heating Capacity per Meter
    27.8, !- Rated Heating Room Air Hot Water Temperature Difference
    5.2E-5, !- Rated Hot Water Volume Flow Rate per Meter
    CapModFuncOfTempDiff, !- Beam Heating Capacity Temperature Difference Modification Factor Curve or Table Name
    HeatCapModFuncOfSAFlow, !- Beam Heating Capacity Air Flow Modification Factor Curve or Table Name
    CapModFuncOfWaterFlow; !- Beam Heating Capacity Hot Water Flow Modification Factor Curve or Table Name

Now look at the induction unit example file. 5ZoneFPIU.idf.

This objects has 3 air nodes, 2 sets of water nodes, and a mixer object.

  AirTerminal:SingleDuct:ConstantVolume:FourPipeInduction,
    SPACE1-1 FPIU,           !- Name
    ReheatCoilAvailSched,    !- Availability Schedule Name
    autosize,                !- Maximum Total Air Flow Rate {m3/s}
    1.0,                     !- Induction Ratio
    SPACE1-1 ATU Supply Node,!- Supply Air Inlet Node Name
    SPACE1-1 ATU Induc Node, !- Induced Air Inlet Node Name
    SPACE1-1 In Node,        !- Air Outlet Node Name
    SPACE1-1 HW Coil Water In Node,  !- Hot Water Inlet Node Name
    SPACE1-1 CW Coil Water In Node,  !- Cold Water Inlet Node Name
    Coil:Heating:Water,      !- Heating Coil Object Type
    SPACE1-1 HW Coil,        !- Heating Coil Name
    autosize,                !- Maximum Hot Water Flow Rate {m3/s}
    0.0,                     !- Minimum Hot Water Flow Rate {m3/s}
    0.002,                   !- Heating Convergence Tolerance
    Coil:Cooling:Water,      !- Cooling Coil Object Type
    SPACE1-1 CW Coil,        !- Cooling Coil Name
    autosize,                !- Maximum Cold Water Flow Rate {m3/s}
    0.0,                     !- Minimum Cold Water Flow Rate {m3/s}
    0.002,                   !- Cooling Convergence Tolerance
    SPACE1-1 ATU Mixer;      !- Zone Mixer Name

Here's how I would make this change.

Using a text editor:

1) find the coils and mixer ... (more)