Bryant 315AAV Error Code Rapid Flashing: Line Voltage Polarity Reversed
What Does Code Rapid Flashing Mean?
When the diagnostic LED on the Bryant 315AAV control board flashes rapidly without a pause, the integrated furnace control has detected that 115VAC line voltage polarity is reversed at the furnace. The hot and neutral conductors are swapped.
Reversed polarity prevents the furnace from operating because the control board's internal 24VAC circuit relies on correct phase relationship between the incoming hot and neutral conductors. The board detects the reversed polarity and locks out heating to protect sensitive electronics from potential damage.
Correcting this requires verifying which conductor is the hot line with a voltage meter and swapping the wires at the furnace disconnect box or junction box to restore proper polarity. This work must be performed with power off by a qualified electrician or HVAC technician, as it involves 115VAC line voltage connections.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Reversed line voltage wiring (hot and neutral swapped) | Most common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- Call a licensed electrician or HVAC technician to correct the reversed polarity — line voltage work must be done safely with power off
- Do not attempt to swap line voltage wires without proper training and test equipment
✓ Verified against manufacturer service manual — March 2026