| Group code | Specific code | DESCRIPTION |
| H01 | .00 | Communication error between gas valve and PCB |
| H01 | .05 | Max temperature difference between flow and return exceeded |
| H01 | .08 | CH flow temperature increasing too fast |
| H01 | .14 | Max flow temperature exceeded |
| H01 | .18 | No circulation of water |
| H01 | .21 | DHW flow temperature increasing too fast |
| H02 | .02 | Not applicable to this appliance |
| H02 | .03 | Not applicable to this appliance |
| H02 | .04 | Not applicable to this appliance |
| H02 | .06 | Low system water pressure |
| H03 | .00 | Communication error with NTC flue sensor |
| H03 | .01 | Communication error with the HMI PCB |
| H03 | .02 | No flame during operation |