| Fault Description |
System Behaviour |
| T1 |
Ignition test – checking the igniter spark |
| T2 |
Fan test – checking the basic fan |
| T3 |
Pump test – checking the basic pump |
| T4 |
Three way valve test |
| T6 |
Ionisation oscillator test |
| 9A 362 |
error – incorrect HCM fitted |
| 9U 233 |
Heat Control Module (HCM) error – problem with code plug |
| B7 257 |
Internal error – possible control board problem |
| C6 215 |
Fan problem – fan running too fast |
| C7 214 |
Fan problem – fan not running |
| D1 240 |
Return sensor error – sensor may be wet or damaged |
| E2 222 |
Flow sensor short circuit error |
| E5 218 |
Flow temperature too high |
| E9 219 |
Safety sensor fault – temperature too high, sensor short circuit or open circuit |
| EA 227 |
No flame detected or flame signal loss during operation |
| F0 237 |
Internal error |
| F7 228 |
Flame error – false flame or flame detected before burner started |
| FA 306 |
False flame fault – flame detected after burner stop |
| FD 231 |
Mains power fault – electrical power interruption |
| FA 364 |
Gas valve EV2 leak test failed – gas valve leak |
| FB 365 |
Gas valve EV1 leak test failed |
| A1 281 |
Pump stuck or running with air in the system |
| C1 264 |
Airflow stopped during operation |
| C4 273 |
Airflow present during last 24 hour |
| D1 240 |
Return sensor short circuit |
| D4 271 |
Temperature difference between flow and safety sensor exceeds limit |
| E9 224 |
Max thermostat activated – flue gas thermostat overheat |
| EA 227 |
No ionisation detected after ignition |
| EF 349 |
Central heating boil detected – boiler operating at minimum burner load with temperature difference greater than 18°C between Flow & Return. |
| NO CODE 212 |
Safety or flow temperature rising too fast |
