Results 1 to 5 of 5
  1. #1
    Join Date
    Jul 2005
    Can any body explain the reason carrier grounds 24 volt
    common leg to frame while most other manufactures do not,
    what purpose does it serve???

  2. #2
    Join Date
    Mar 2005
    burlington county n.j.
    lennox has been doing this for years. not sure why probably for ignition controls.

  3. #3
    Join Date
    Oct 2005
    Fairfax, VA
    The purpose of having a low voltage system is safety for the operators, and grounding one leg ensures that it stays less than 30 v. Without the tie-down, the voltage can float around with respect to ground. In other words, you can measure 24v from line to line, and still have 50v to ground (called a bias voltage in electronics).

  4. #4
    Join Date
    Apr 2004
    Most do, sometimes it's not as apparent though. Sometimes its just a trace on the board that connects to one of the mounting screws.

  5. #5
    Join Date
    Nov 2000
    Eastern PA
    It's needed for the new flame sensors and ignition boards to function. The board sends a milivolt charge to the flame sensor which must travel through the flame to ground which then goes back to the board to complete the circuit telling the board that there is indeed a flame.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV

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