Coleman DGAA056BDTA Error Code Rapid Flashes: Reverse Polarity
What Does Code Rapid Flashes Mean?
Rapid flashing on the Coleman DGAA056BDTA indicates reversed line voltage polarity — the hot and neutral wires feeding the furnace are connected backwards. Unlike some furnace models where reversed polarity only affects heating, the Coleman DGAA warns that both heating and cooling operations are impacted by this condition.
Reversed polarity compromises the furnace's flame sensing circuit, which relies on the voltage difference between the grounded burner assembly and the hot conductor to generate a measurable microamp signal at the flame sensor. With the polarity swapped, this circuit cannot function reliably. Additionally, the connected air conditioning system may also be affected because it shares the same electrical supply.
This is an electrical wiring problem, not a furnace defect. The polarity reversal could be at the furnace junction box, the disconnect switch, or the circuit breaker panel. A licensed electrician or HVAC technician should check the wiring at each connection point and correct the hot and neutral positions. Both the furnace and any connected cooling equipment should be tested after the correction.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Line voltage wires reversed at furnace connection | Most common | ✗ Call a pro → |
| Reversed polarity at electrical outlet | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- Immediately when this code appears — reversed polarity affects both heating and cooling and requires professional electrical correction
✓ Verified against manufacturer service manual — March 2026