.
Idle mode (decimal blinks at 1 Hz)
This code typically points to
- No active service demand
Next checks to confirm
- Verify no W/Y/G demand if idle is unexpected
Escalation
None
Reset behavior
Not a fault.
Informational
No action needed
Fault Code Lookup
HVAC Sales Master
Source
Lennox unit information doc 100027, integrated diagnostic/status table, p.10