55 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 →
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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 main internal computer or memory chip has developed a communication fault or has failed, meaning the unit cannot safely control the heating process.
Your boiler has logged a note that a technician's diagnostic tool was plugged in while viewing the error history, but this itself is not a functional breakdown.
Your boiler's internal computer parts are unable to communicate with each other due to a software mismatch.
Your boiler has detected an issue with the quality of the electricity supply coming into your home, meaning it cannot operate safely.
Your boiler is not receiving enough electrical power from the main supply to operate safely and has shut down as a precaution.
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 is struggling to move water through the system, either because the pump is jammed or there is not enough water present.
Your boiler is struggling to operate because the electrical power reaching it is unstable, insufficient, or the control module has failed to recognize the incoming voltage.
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's internal computer has developed a fault and can no longer communicate with the main control system.
Your boiler has stopped working because the internal fan, which safely removes waste gases, is not spinning fast enough.
Your boiler's fan has unexpectedly stopped working while the unit was running, causing the system to shut down for safety.
Your boiler's main internal computer has developed a serious electronic fault and can no longer control the heating process safely.
Your boiler has stopped working because the internal fan has been running non-stop for too long, causing the system to shut down for safety.
Your boiler has detected that the internal fan is spinning faster than it should, which has caused the system to shut down for safety.
Your boiler's fan is failing to start up, which means the system cannot safely clear waste gases and will not allow the boiler to ignite.
Your boiler has stopped working because the fan that clears exhaust gases is not spinning at the correct speed.
Your boiler has shut down because the internal fan, which safely clears waste gases, has stopped spinning while the boiler was running.
Your boiler has lost communication with its outdoor temperature sensor, meaning it won't be able to adjust its energy use based on the weather outside.
Your boiler is overheating because water is not moving through the system quickly enough to carry the heat away.
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 detected an electrical fault with the internal sensor that monitors the temperature of the water leaving the unit, preventing it from heating up safely.
Your boiler has lost communication with the internal thermometer that monitors water temperature, causing the system to shut down for safety.
Your boiler has detected a fault with the sensor that monitors the water temperature leaving the unit, causing it to shut down for safety.
Your boiler has lost its connection to the component that monitors water temperature, meaning it cannot safely heat your home or water until the connection is restored.
Your boiler has overheated, prompting a safety sensor to shut the system down to prevent damage.
Your boiler has shut down because the water inside it has become dangerously hot.
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 is failing to detect a flame when it tries to start, which means it will not provide any heating or hot water until the issue is resolved.
Your boiler has lost its flame suddenly while it was running, causing it to stop heating your home for safety.
Your boiler's internal computer brain has encountered a communication error and is preventing the system from starting for safety.
Your boiler's internal computer or control module has developed a fault and can no longer communicate with the rest of the system.
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 has detected an internal electrical problem with the component that controls the gas supply, causing the system to shut down for safety.
Your boiler's internal computer has encountered a critical communication error and cannot safely operate your heating or hot water.
Your boiler's internal computer has encountered a critical communication error and cannot operate safely.
Your boiler's internal computer has encountered a critical communication failure or hardware fault, meaning it cannot process commands to heat your home.
Your boiler's main internal computer or its configuration chip has developed a fault and can no longer communicate correctly with the rest of the system.
Your boiler's internal computer has encountered a critical communication error and cannot tell the system to start heating.
Your boiler's internal computer has encountered a critical error or is not communicating properly, meaning the system cannot run.
Your boiler’s internal computer has lost contact with a vital control chip, meaning the system cannot run safely and will stay locked out.
Your boiler's main internal computer or its configuration module has developed a communication failure, preventing the system from operating safely.
Your boiler's internal computer has developed a fault and can no longer communicate with the main control system, meaning it cannot operate safely.
Your boiler detects a flame when there shouldn't be one, so it has shut down as a safety precaution to prevent gas from flowing incorrectly.
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 is still detecting a flame even though the gas supply should have been cut off, which is a safety concern that prevents the unit from operating.
Your boiler has entered a temporary standby mode because the reset button was pressed accidentally or held down for too long.
Your boiler has lost power or experienced an electrical error while it was already trying to show a different fault code.
Your boiler is currently running a maintenance check at its maximum power, which is a normal process and not a fault with the system.
BoilerFaultCodes