What It Means
- Incompatible Equipment Detected
Lennox Equipment not specified
Lennox Equipment not specified Error Code 21
Equipment not specified:
Causes & actions from Lennox
How it shows
- iComfort S30 alert: 21
Priority condition: Service Urgent Equipment is trying to be utilized that is not compatible with other system components, such as a single-stage non-variable speed motor furnace with a modulating outdoor unit.
Applicable models & manual sources
- iComfort S30
Incompatible Equipment Detected
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.
