Lennox Unit controller

Lennox Error Code 516

Unit controller

What It Means

  • INVALID DIN NUMBER

Causes & actions from Lennox

How it shows
  • M4 alarm code: 516

Invalid DIN number received from M4 unit controller. Indicates DIN incompatibility

Applicable models & manual sources
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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