11 / E11

System start-up test is required or in progress; installer should navigate to thermostat menu to run system start-up test; code clears once testing is complete

This code typically points to

Incomplete system start-up test
System start-up test is running

Next checks to confirm

Run the SYSTEM START-UP TEST from thermostat/install setup following outdoor unit installation manual

Escalation

Thermostat-only commissioning/test-state message

Reset behavior

Clears automatically once testing is complete.

Informational

No action needed