14 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar 8000 Life
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. 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 |
|---|---|---|
| 47-406-65 | Greenstar 29CDi Classic ErP | 2015–2019 |
| 47-406-66 | Greenstar 29CDi Classic ErP LPG | 2015–2019 |
| 47-406-67 | Greenstar 34CDi Classic ErP | 2015–2019 |
| 47-406-68 | Greenstar 34CDi Classic ErP LPG | 2015–2019 |
| 47-406-69 | Greenstar 38CDi Classic ErP | 2015–2019 |
| 47-406-70 | Greenstar 38CDi Classic ErP LPG | 2015–2019 |
| 47-406-71 | Greenstar 42CDi Classic ErP | 2015–2019 |
| 47-406-72 | Greenstar 42CDi Classic ErP LPG | 2015–2019 |
| 47-311-93 | Greenstar CDi 30 CDi | 2005–2007 |
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Your boiler is failing to light the flame needed to produce heat or hot water, causing it to lock itself out for safety.
Your boiler's computer chip has failed or is recognized as incorrect, meaning the main brain of the boiler cannot talk to its control board.
Your boiler has detected that there is not enough water circulating through the system, which could be due to a leak or a mechanical issue with the pump.
Your boiler's hot water sensor has failed or has a broken connection, meaning you likely won't have any hot water.
Your boiler has lost its connection to the external heating controls, meaning it cannot receive instructions on when to turn on or off.
Your boiler's computer memory chip is loose or missing, meaning the system doesn't know which model it is and has stopped working for safety.
Your boiler has stopped working because the internal fan, which safely removes waste gases, is not spinning fast enough.
Your boiler has detected a fault with the sensor that monitors the temperature of the water leaving the unit, preventing it from heating your home safely.
Your boiler has sensed that it is getting too hot and has automatically shut down for safety.
Your boiler has stopped working because it cannot light a flame, most likely due to an interruption in the gas supply or a part that has worn out.
Your boiler has experienced an internal electrical communication error, which means the main control box cannot talk to the internal components correctly.
Your boiler thinks it sees a flame even though it should be turned off, which prevents it from starting up safely.
Your boiler is still detecting a flame even after it has been told to shut down, which indicates a potential safety issue with the gas supply inside the unit.
Your boiler has entered a temporary standby mode because the reset button was pressed accidentally or held down for too long.
BoilerFaultCodes