Outdoor unit not found
Wall control cannot find outdoor unit on ABCD communication bus during initial Connex discovery/commissioning. COMMISSIONING-TIME DIAGNOSTIC — not a runtime fault. Appears during initial system setup, not during normal operation.
This code typically points to
- ABCD wiring not connected between indoor unit/wall control and outdoor unit
- Outdoor unit disconnect not turned on during discovery
- Outdoor unit power not yet established (e.g., 24V transformer issue)
- ABCD polarity reversed at outdoor unit
- Open or shorted ABCD conductors between indoor and outdoor
- Failed outdoor board or VFD preventing communication at startup
- Wrong model plug installed preventing outdoor from responding properly
Next checks to confirm
- Verify outdoor disconnect is ON and line voltage is present
- Verify 24V power at outdoor control board
- Verify ABCD wiring from indoor to outdoor with correct polarity
- Verify correct model plug is installed on outdoor board
- Verify no shorts, opens, or high resistance on ABCD between indoor and outdoor
- On 186CNV/284ANV inverter outdoor, check COMM light and VFD Comm light state
- Retry Connex discovery sequence
Escalation
If wiring, power, and model plug verified but outdoor still not discovered, outdoor board or VFD failure becomes likely.
Reset behavior
Clears when outdoor unit is successfully discovered during next commissioning attempt.
Urgent
Fix now