51 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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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 |
|---|---|---|
| 41-311-75 | Greenstar 15Ri | 2005–2015 |
| 41-311-76 | Greenstar 15Ri | 2005–2015 |
| 41-311-77 | Greenstar 18Ri | 2005–2015 |
| 41-406-54 | Greenstar 27Ri Compact ErP | 2015–present |
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Your boiler's computer chip is struggling to communicate because it has an outdated or mismatched software version that doesn't match the rest of the system.
Your boiler has detected an issue with the electricity supply it is receiving, which is causing the system to stop working as a safety precaution.
Your boiler has detected that the electricity supply coming from your home's mains is inconsistent or too low to operate the internal electronics safely.
Your boiler's internal computer is having a communication error and cannot identify its own settings, meaning the system has shut down for safety.
Your boiler is struggling to detect the flame correctly, so it has safely shut itself down to prevent any issues.
Your boiler has detected that the internal water pump is not spinning correctly, which prevents heat from being moved around your home.
Your boiler is having trouble measuring the temperature of your hot water, which usually means it cannot heat it safely or effectively.
Your boiler is struggling to accurately measure the temperature of your hot water, which may lead to no hot water or inconsistent temperatures.
Your boiler's internal computer has lost its connection with the main control board, meaning the system cannot communicate correctly to heat your home.
Your boiler's internal computer is having a communication error and cannot recognise its own control settings, meaning it will not operate.
Your boiler's internal computer memory chip is loose or missing, meaning it cannot identify which model it is supposed to be.
Your boiler has detected an internal software or communication error that is preventing it from operating correctly.
Your boiler has detected an issue with the air or exhaust system, meaning it cannot safely clear waste gases and has shut itself down to prevent a hazard.
Your boiler has detected an internal electronic error that is preventing it from starting up correctly.
Your boiler is struggling to clear exhaust gases properly, so it has safely shut itself down to prevent any risk of fumes entering your home.
Your boiler's fan is spinning faster than it should, which means the system has safely shut down to prevent any damage.
Your boiler is struggling to clear exhaust gases properly, so it has safely shut itself down to prevent any unsafe buildup.
Your boiler is struggling to clear exhaust gases properly, so it has safely shut itself down to prevent any risk.
Your boiler has detected an issue with the internal fan that pushes exhaust gases out of your home, so it has safely shut itself down to prevent any risk.
Your boiler has detected an issue with the internal airflow system, which means it has safely shut itself down to prevent it from operating incorrectly.
Your boiler is struggling to read the outdoor temperature, so it is defaulting to a standard internal setting to keep your heating running.
Your boiler is shutting down because the water inside is heating up much faster than the system can move it around, which usually points to a blockage or a pump issue.
Your boiler has lost track of the temperature of the water flowing through it because an internal sensor is broken.
Your boiler is struggling to detect the flow of water through the system, meaning it cannot reliably provide heating or hot water.
Your boiler is currently unable to detect the flow of water, which means it will not turn on your heating or hot water to prevent internal damage.
Your boiler is struggling to detect the flow of water through the system, which means it has safely shut down to prevent overheating.
Your boiler is currently unable to detect the movement of water, which means it has stopped heating your home to prevent potential damage to its internal components.
Your boiler has got too hot and has automatically shut down for safety to prevent damage.
Your boiler has detected that it is running too hot and has automatically shut down to prevent damage.
Your boiler has stopped working because it cannot detect the flow of water correctly, meaning it does not know if it is safe to ignite the burner.
Your boiler has failed to light, which most likely means the gas supply is interrupted or there is a blockage preventing the burner from starting.
Your boiler is failing to light the flame properly, so it has shut down as a safety precaution.
Your boiler is failing to light the flame properly, which means it has automatically shut down to keep your home safe.
Your boiler is failing to light the internal flame, which means it has stopped producing heat and hot water as a safety precaution.
Your boiler has detected a serious internal electronic issue that is preventing it from operating correctly.
Your boiler's internal computer has encountered a glitch or a hardware failure, preventing it from running properly.
Your boiler's computer is experiencing a internal processing error and has shut down to prevent damage, meaning you currently have no heating or hot water.
Your boiler has detected an internal software or electronic communication issue that is preventing it from operating safely.
Your boiler has detected an internal software or electronic communication error that prevents it from operating safely.
Your boiler has detected a critical internal software or electronic control fault that is preventing it from operating safely.
Your boiler has detected an internal computer communication error, meaning it has safely shut down to prevent further issues.
Your boiler's computer has encountered an internal communication error and has safely shut itself down to prevent any further issues.
Your boiler has detected a serious internal processing error that prevents it from operating safely, requiring a qualified technician to investigate.
Your boiler has encountered an internal electronic error that is preventing it from starting up correctly.
Your boiler's computer is experiencing an internal glitch and cannot communicate with the system to operate your heating or hot water.
Your boiler thinks it can still see a flame inside after it has been told to turn off, which is a safety conflict.
Your boiler is failing to light the flame properly, meaning it cannot provide heating or hot water until the issue is resolved.
Your boiler thinks a flame is still present even though the gas should have been turned off, which is a safety concern that prevents it from running.
Your boiler has detected a problem with the internal mechanism that controls the gas supply, meaning it cannot safely start up to provide heat or hot water.
Your boiler is temporarily confused because the reset button was held down for too long or pressed when it wasn't needed.
Your boiler has detected a temporary loss of electrical power or a loose internal connection, causing it to shut down for safety.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes