Lennox Air handler

Lennox Error Code 604

Air handler: Air handler (indoor)

What It Means

  • Error of communication down between the indoor unit and wired remote controller after completion of 10 times tracking.

Causes & actions from Lennox

How it shows
  • Wired controller display: 604

This manual entry does not list further causes or actions.

Applicable models & manual sources
  • MMD***M6-1P

    Error of communication down between the indoor unit and wired remote controller after completion of 10 times tracking.

    MMD***M6-1P manual, page 65

  • MMD***S6-1P

    Error of communication down between the indoor unit and wired remote controller after completion of 10 times tracking.

    MMD***S6-1P manual, page 69

Disclaimer: This information is for general reference. Code wording and instructions vary by model. Always follow the service manual for your exact unit.

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