14 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar 8000 Lifestyle
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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 |
|---|---|---|
| 47-406-25 | Greenstar Highflow 550 CDi | 2008–2015 |
| 47-406-27 | Greenstar Highflow 550 CDi | 2008–2015 |
| 47-406-24 | Greenstar Highflow 440 CDi | 2008–2015 |
| 47-406-26 | Greenstar Highflow 440 CDi | 2008–2015 |
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Your boiler is having trouble measuring the temperature of the water stored in its internal hot water tank, which means it cannot reliably provide hot water.
Your boiler is having trouble sensing the temperature of your hot water supply, which means it cannot heat your taps or shower correctly.
Your boiler's internal computer is having trouble talking to its main control unit, which prevents it from operating correctly.
Your boiler's internal computer is failing to communicate with a small identity chip, which prevents it from knowing how to operate correctly.
Your boiler's main control computer is experiencing an internal electronic fault and has stopped the system from operating to keep you safe.
Your boiler has detected that the internal fan responsible for safely venting exhaust gases is not working correctly, causing the system to stop heating to ensure your safety.
Your boiler has detected that the water temperature has risen too high and has safely shut itself down to prevent damage.
Your boiler has detected that waste water cannot drain away properly, so it has shut down to prevent internal water damage.
Your boiler has detected that the water stored inside its internal heating tank has become too hot, causing the system to shut down for safety.
Your boiler's temperature sensor is faulty, meaning it cannot accurately read how hot the water is, so it has safely shut down to prevent overheating.
Your boiler has detected that it has become dangerously overheated and has safely shut itself down to prevent internal damage.
Your boiler's computer system has encountered a major internal software or hardware failure and can no longer operate safely.
Your boiler has detected an internal software error and has automatically shut down to prevent incorrect operation.
Your boiler is continuing to detect a flame even after it has attempted to turn off, which indicates a serious safety issue that requires immediate professional attention.
BoilerFaultCodes