| Group code | Specific code | DESCRIPTION | Group code | Specific code | DESCRIPTION |
| E00 | .04 | Return sensor open circuit | E02 | .47 | External device connection error |
| E00 | .05 | Return sensor short circuit | E04 | .48 | External device configuration error |
| E01 | .02 | High temp recorded at return sensor | E04 | .00 | Gas valve fault |
| E01 | .04 | 5 x flame loss in 2hrs with burner on | E04 | .01 | Flow temp sensor short circuited |
| E01 | .11 | Incorrect fan speed | E04 | .02 | Flow temp sensor open circuited |
| E01 | .17 | No circulation | E04 | .03 | Critical flow temperature reached |
| E01 | .20 | Maximum flue gas temp reached | E04 | .04 | Flue temp sensor short circuited |
| E02 | .00 | Boiler reset in progress | E04 | .05 | Flue temp sensor open circuited |
| E02 | .07 | Low system water pressure | E04 | .06 | Critical flue gas temp reached |
| E02 | .16 | On board CSU time out | E04 | .08 | Maximum safe temp reached |
| E02 | .17 | Permanent loss of communication | E04 | .10 | 5 x burner start up failures |
| E02 | .19 | Jumper 1 changed | E04 | .12 | False flame signal |
| E02 | .20 | Jumper 2 changed | E04 | .13 | Fan rotor blocked |
| E02 | .21 | Jumper 3 changed | E04 | .17 | Problem on the gas valve |