A light on your boiler will flash to indicate that there is a fault. Depending on the type of fault, the light will flash in a different sequence.
There will be 4 quick flashes followed by a 5 second gap when the light is off and finally a series of longer flashes. The number of long flashes tells you which fault the boiler has.
| Fault Description | System Behaviour |
|---|---|
| Light off | No boiler demand |
| Light on | Heating demand on boiler is OK |
| 1 flash 5 seconds off | No ionisation detected after ignition |
| 2 flashes 5 seconds off | Loss of ionisation signal during operation |
| 3 flashes 5 seconds off | Gas valve error |
| 4 flashes 5 seconds off | First safety timing error / ignition timing error |
| 5 flashes 5 seconds off | Ionisation detected after burner stopped Gas valve EV2 leak test failed Gas valve EV1 leak test failed Ionisation current detected before burner start Gas valve error Ionisation sensor shorted |
| 4 flashes 5 second gap 1 long flash | Sensor test failed |
| 4 flashes, 5 second gap, 2 long flashes | Safety temperature too high |
| 4 flashes, 5 second gap, 3 long flashes | Max safety thermostat activated |
| 4 flashes, 5 second gap, 4 long flashes | Return temperature too high |
| 4 flashes, 5 second gap, 5 long flashes | Flow temperature too high – supply sensor exceeded 110°c |
| 1 long flash, 4 quick flashes, 5 second gap, 1 long flash, 4 quick flashes | Heating control module (HCM) defective |
| 2 long flashes, 4 quick flashes, 5 second gap, 2 long flashes, 4 quick flashes | Fan running too fast Fan running too slow No airflow after defined period of time Fan not running |
| 3 long flashes, 4 quick flashes, 5 second gap, 3 long flashes, 4 quick flashes | Mains voltage interrupted after locking error |
| 4 long flashes, 4 quick flashes, 5 second gap, 4 long flash, 4 quick flashes | Internal control board faults |
| 5 long flashes, 4 quick flashes, 5 second gap, 5 long flash, 4 quick flashes | All other miscellaneous faults – reset the boiler by turning the control knob anti-clockwise to the reset position |
