RAPID FLASHING
Reversed 115 VAC polarity
This code typically points to
- Reversed line/neutral
- Improper grounding
- Wiring error
Next checks to confirm
- Verify polarity first
- Verify furnace grounding
- Verify supply wiring
Escalation
Persistent rapid flash with verified supply wiring points to control/wiring abnormality.
Reset behavior
Clears when polarity issue is corrected.
Urgent
Fix now