23 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: 28i Junior
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 has detected an internal fault preventing it from lighting, most likely caused by a failed safety sensor or a malfunction in the ignition sequence.
Your boiler is currently taking a mandatory rest period to prevent the system from overheating, and it will attempt to restart automatically once the internal temperature has dropped.
Your boiler has detected an internal safety lockout error, causing it to stop operating to prevent potential damage or overheating.
Your boiler has detected a safety concern or internal fault and has automatically shut down to protect itself, requiring you to attempt a manual reset.
Your boiler is currently stuck in a manual service mode used by engineers to perform system tests, rather than experiencing an actual breakdown.
Your boiler has detected that the internal temperature is very low and has automatically activated its built-in frost protection mode to prevent the system from freezing.
Your boiler has automatically turned itself off because the water inside it is getting too hot, likely due to a circulation problem.
Your boiler has automatically turned off because the hot water inside it has become dangerously hot.
Your boiler is not receiving any power, meaning it cannot start up to provide your home with heating or hot water.
Your boiler has stopped working because a critical internal electrical component has failed, cutting power to the system's main brain.
Your boiler is currently waiting for a signal from your heating controls, but it isn't receiving the instruction to turn on.
Your boiler's electronic control system is experiencing a fault, which is preventing it from starting up or operating correctly.
Your boiler is failing to detect that water is moving through the system, which is preventing it from safely starting your heating or hot water.
Your boiler is struggling because the surrounding area is freezing, which has triggered a built-in safety mode to prevent internal pipes from icing up.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent damage to its internal components.
Your boiler is failing to light the internal flame, which means it has safely shut itself down to prevent a gas build-up.
Your boiler has detected an issue with its internal sensors or electrical connections, which has caused it to stop working to avoid potential damage.
Your boiler is having trouble breathing, likely because air isn't moving through the flue correctly or a sensor is misreading the airflow.
Your boiler is failing to light the gas burner because it is not receiving the correct signal to start the heating process.
Your boiler's electronic command center has encountered a serious internal error and is unable to safely control the unit's operation.
Your boiler is operating normally, as the fan is running to help manage the water temperature inside your heating system.
Your boiler is failing to light the flame properly, so it has purposefully shut down to prevent gas from building up inside.
Your boiler has sensed that it is dangerously overheating and is running the pump constantly to try and cool itself down.
BoilerFaultCodes