York Gas Furnace: P3DH/P3DN
Re: Lockout Codes
| Red Light Status | Description |
| On | Faulty Control |
| Rapid Flash | Low Flame Sense Signal |
| 1 | Lockout Caused by Flame Sensed |
| 2 | Pressure Switch Stuck Closed |
| 3 | Pressure Switch Stuck Open |
| 4 | High Limit or Blower Limit Open |
| 5 | Rollout Switch Open or Rollout Sensed |
| 6* | Lockout Caused by Pressure Switch (3 times) |
| 7* | Failed to Ignite (3 tries) |
| 8* | Loss of Flame (5 times) |
| 9 | Reversed Polarity |
| 11 | Improper Ground or Missing Jumper |
| * = Lockout will Auto-Reset After 1 Hour | |