What It Means
- UNIT OPERATING IN BACKUP MODE
Lennox Unit controller
Lennox Error Code 93
Unit controller
Causes & actions from Lennox
How it shows
- M4 alarm code: 93
• Check communication loss with network sensor or if CORE Unit Controller If NETWORK INTEGRATION is set to RTU STANDALONE MODE and backup sensor is set to RETURN AIR BACKUP. • While running in backup mode the unit controller will set this alarm. The unit controller will return from Backup mode to Primary (Main) mode on a reset or after the Primary mode (room Sensor is not in error or OR network communication is re-established and available for 300 seconds. • Backup mode alarm will be cleared on the reset OR after the unit controller has returned to primary (main) system mode.
Applicable models & manual sources
- MODEL L - M4 UNIT CONTROLLER
UNIT OPERATING IN BACKUP MODE
MODEL L - M4 UNIT CONTROLLER, M4 Unit Controller
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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