Lennox Unit controller

Lennox Error Code 73

Unit controller

What It Means

  • NETWORK SENSOR

Causes & actions from Lennox

How it shows
  • M4 alarm code: 73

Check with integrator for refresh rate, network status lights and wiring.

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.

What should you check next?

Continue in ACLogics with guided diagnosis for your equipment and symptoms.

See how guided diagnosis works →