BoilerFaultCodesMain System 18 24 28 HE Fault codes & diagnostics
0 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
System Natural Gas 18-28 kW 2006-2011 Discontinued
GC Numbers 41-467-0141-467-0241-467-03
Download the Main System 18 24 28 HE manual
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Versions & GC numbers
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-467-02 | System 24 HE | 2006–2011 |
| 41-467-03 | System 28 HE | 2006–2011 |
Status & diagnostic codes 9 operating states & engineer diagnostics
Not faults — these are normal operating states. Tap to expand.
9 operating states & engineer diagnostics
Not faults — these are normal operating states. Tap to expand.
20 Status Your boiler has stopped working because it cannot light its burner or drain away waste water properly. 21 Status Your boiler has automatically shut down because it has detected that its internal safety components have reached an dangerously high temperature. 22 Status Your boiler is struggling to clear exhaust gases safely, so it has turned itself off to prevent any risk. 23 Status Your boiler is struggling because there is not enough water pressure in the system to keep it running smoothly. 24 Status Your boiler has stopped working because it is unable to accurately measure the temperature of the water inside the system, so it has shut down to stay safe. 25 Status Your boiler has stopped working because it cannot accurately tell how hot the water inside it is, so it has shut down as a safety precaution. 26 Status Your boiler has just been turned on or has experienced a brief power cut and is currently going through its standard startup sequence. 27 Status Your boiler is operating normally and performing its standard heating cycles as intended. 28 Status Your boiler is operating exactly as it should and is currently burning gas to heat your home or water.