9 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar 8000 Life Regular
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
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 |
|---|---|---|
| 41-406-33 | Greenstar 30 CDi Classic Regular | 2014–2015 |
| 41-406-34 | Greenstar 30 CDi Classic Regular | 2014–2015 |
| 41-406-35 | Greenstar 40 CDi Classic Regular | 2014–2015 |
| 41-406-36 | Greenstar 40 CDi Classic Regular | 2014–2015 |
| 41-406-05 | Greenstar FS 30 CDi Regular | 2008–2015 |
| 41-406-06 | Greenstar FS 42 CDi Regular | 2008–2015 |
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Your boiler's internal computer is failing to recognise a specific electronic memory chip that tells it how to operate correctly.
Your boiler is struggling to push air through its system properly, which has caused it to stop working to keep you safe.
Your boiler has lost the ability to accurately measure the temperature of the water used for your heating system, so it has safely shut down to prevent overheating.
Your boiler has detected that it is overheating and has automatically shut itself down to prevent damage.
Your boiler has stopped working because it is unable to light the flame properly or keep it burning.
Your boiler has detected an internal software or electronic fault that prevents the system from operating safely.
Your boiler is detecting a flame inside even though it has been told to turn off, which means it cannot safely control its operation.
Your boiler has detected that a flame is still present even though it has attempted to turn the gas off, which indicates a potential safety issue with the internal gas valve.
Your boiler is simply indicating that the reset button has been triggered, likely by being pressed accidentally instead of the standard operation button.
BoilerFaultCodes