| ZHE(E) | 0100 | Internal fault in control unit |
| ZHE(E) | 0101 | Control module interlock |
| ZHE(E) | 0200 | EOL programming not carried out. |
| ZHE(E) | 0300 | No start |
| ZHE(E) | 0400 | Flame-out during operation |
| ZHE(E) | 0500 | Undervoltage supply |
| ZHE(E) | 0501 | Overvoltage supply |
| ZHE(E) | 0600 | Flame monitor has Short circuit to ground. |
| ZHE(E) | 0601 | Flame monitor has Open circuit. |
| ZHE(E) | 0700 | Overheating of auxiliary heater |
| ZHE(E) | 0800 | Temperature sensor has Short circuit to ground. |
| ZHE(E) | 0801 | Temperature sensor has Open circuit. |
| ZHE(E) | 0900 | Flame monitor signals 'bright' before combustion mode. |
| ZHE(E) | 1000 | Solenoid valve circuit has Short circuit to ground. |
| ZHE(E) | 1001 | Solenoid valve circuit has Open circuit. |
| ZHE(E) | 1100 | Combustion air blower circuit has Short circuit to ground. |
| ZHE(E) | 1101 | Combustion air blower circuit has Open circuit. |
| ZHE(E) | 1200 | Spark ignition generator circuit has Short circuit to ground. |
| ZHE(E) | 1201 | Spark ignition generator circuit has Open circuit. |
| ZHE(E) | 1300 | Circulation pump circuit has Short circuit to ground. |
| ZHE(E) | 1301 | Circulation pump circuit has Open circuit. |