Results 1 to 5 of 5
  1. #1
    Join Date
    May 2008

    Lennox Comfortsense 7000 Question

    My new comfortsense 7000 thermostat has an error reading "HVAC Error Detected". My installer checked the L input and everything on the HP and furnace checked out fine. Installer was on hold with Lennox for almost an hour (sitting at my dining room table, so I witnessed it myself), but he still doesn't have an answer. So I thought I would be "pro" active and ask you guys if you have any idea as to what may be the cause of the error message. Could it have something to do with the outdoor sensor that is wired but not yet physically installed?


  2. #2
    The "HVAC ERROR DETECTED" only pertains to an LSOM error. The outdoor sensor comes factory default set to NO. It would not give this error. Looks like the error is coming from the LSOM working properly. He needs to check the outdoor unit for a problem. This is the notes from Lennox on that error:

    "L" input from the equipment is used to notify the user of an equipment
    fault by displaying HVAC ERROR DETECTED" when one of the following
    conditions exist:
     L" terminal is activated with 24VAC and Y1 has been activated
    for 5 minutes, OR,
     LSOM error signal is detected on L" input and Y1 has been activated
    for 5 minutes.
    NOTE − If system is in battery mode, the L terminal is not functional. The
    L input is used for diagnostic information purposes only, it is not intended
    to provide equipment protection.

    Have him check the heat pump for proper installation and sequence of operation and disconnect the "L" terminal and restart system. If all goes well hook the "L" back up and try again. Also make sure that the tempsensor is set to no in installer setup until the sensor is installed.

  3. #3
    Join Date
    May 2008

    "L" terminal

    Thanks, Socal. He did check the outdoor unit and said it was running perfectly. He was reading the programming manual so he did check the L terminal, although I am not sure if he disconnected it and restarted the system.

  4. #4
    If he is still having problems with it have him try the LSOM installation verification steps described below as well:

    LSOMInstallation verification
    To verify correct LSOM installation, two functional tests
    can be performed. Disconnect power from the compressor
    and force a thermostat call for cooling. The red trip LED
    should turn on indicating a compressor trip as long as
    24VAC is measured at the Y terminal. If the red LED does
    not function as described, refer to table 8 to verify the wiring.
    Disconnect power from the compressor and 24VAC
    power from LSOM. Remove the wire from the Y terminal of
    LSOM and reapply power to the compressor, allowing the
    compressor to run. The yellow alert LED will begin flashing
    a code 8 indicating a welded contactor. Disconnect power
    from the compressor and 24VAC power from the LSOM.
    While the LSOM is off, reattach the wire to the Y terminal.
    Reapply power to the compressor and 24VAC power to the
    LSOM; the yellow alert LED will flash the previous code 8
    for one minute and then turn off. If the yellow LED does not
    function as described, refer to table 8 to verify the wiring.

    Table 8 will be in any manual with a LSOM installed.
    Last edited by socalhvacguy; 07-17-2008 at 08:29 PM. Reason: added info

  5. #5
    Join Date
    Mar 2005
    burlington county n.j.
    would not be the first bad module..........

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event