E349
No 24V between R and O on integrated control with non-communicating outdoor unit; dual-fuel module required for heat-pump application
This code typically points to
- R-to-O configuration link missing
- Incorrect heat-pump / dual-fuel configuration
Next checks to confirm
- Verify heat-pump / dual-fuel wiring and configuration
- Restore or hardwire the R-to-O link as required
Escalation
Critical alert in applicable non-communicating configuration
Reset behavior
Clears once the required configuration link is restored.
Urgent
Fix now