The boiler has stopped itself while it tries to set its gas burning mix correctly, which usually means it needs a qualified engineer to check the flame sensing and flue before it can run safely again.

Fault Eb during automatic calibration of the combustion controller. Check gap between ionisation electrode and burner gauze assembly. Check allocation of gas type (coding address 82, gas train setting). Check flue system; remedy flue gas recirculation if required. Press reset button R.