Lennox XP15 Heat Pump
Re: Defrost Board Diagnostic Codes / Fault Codes
The defrost board uses two LEDs for diagnostics. The LEDs flash a specific sequence according to the condition.
DIAGNOSTIC CODES:
| Green | Red | Description |
| Off | Off | No Power to Control |
| Simultaneous Slow | Normal Operation | |
| Alternating Slow | Anti-Short Cycle Delay | |
| Off | Slow | Low Pressure Fault |
| Off | On | low Pressure Lockout (5 trips) |
| Slow | Off | High Pressure Fault |
| On | Off | High Pressure Lockout (5 trips) |