180 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar 28CDi Compact
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 notifying you that it is currently running, but it has detected a minor inconsistency in how it is circulating water around your system.
Your boiler has detected that water is failing to circulate correctly, so it has temporarily shut down its internal pump to prevent internal damage.
Your boiler is having trouble communicating with your solar water heating system, which means the solar panels may not be contributing to your hot water at the moment.
This code simply indicates that your boiler is currently operating normally to provide heating for your home.
Your boiler is currently focused on heating your hot water and is operating normally.
Your boiler is taking a short rest between heating cycles to prevent rapid stop-start wearing, which is a normal protective feature ensuring it doesn't overheat.
Your boiler is perfectly healthy and is simply waiting for you to turn on a tap or adjust your heating thermostat.
Your boiler has detected that the water inside the unit is getting too hot, so it has safely shut itself down to prevent damage.
Your boiler has been accidentally switched into a specific testing mode used by engineers to check emissions, which prevents it from heating your home normally.
Your boiler is shutting down because it is heating up much faster than it can circulate the water, which often points to a blockage or a pump issue.
Your boiler has stopped working because it detected a problem with the internal fan that pushes exhaust gases out of your home.
Your boiler has detected that the internal fan responsible for venting exhaust gases failed to start properly during its initial safety check.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent any damage or safety issues.
Your boiler is trying to start, but it cannot detect a flame, so it has safely shut itself down to prevent gas from building up.
Your boiler has detected a signal that suggests a flame is present when it should not be, leading the system to shut down for safety reasons.
Your boiler has stopped heating because the flame inside went out while it was trying to run.
Your boiler has been told to stop running by an external device, such as a smart thermostat or a frost protection controller.
Your boiler has lost communication with its internal computer, meaning it cannot safely operate or control your heating and hot water.
Your boiler has detected an issue with the control system that manages the gas supply, so it has safely shut down to prevent any risk.
Your boiler's internal computer is confused because its internal identification settings do not match the specific components installed, causing it to lock itself to prevent incorrect operation.
Your boiler has detected an internal communication error and has safely shut down to prevent potential damage.
Your boiler's internal computer is experiencing a major communication error and is unable to safely control the system.
Your boiler's main control unit is experiencing a communication error or electrical glitch that is preventing it from operating correctly.
Your boiler's main control computer is experiencing a temporary glitch or internal error, which has caused it to stop working for safety reasons.
Your boiler has detected an internal communication error and has safely shut down to prevent potential damage.
Your boiler's internal computer is experiencing a communication error and cannot safely manage the heating or hot water systems.
Your boiler's internal computer is experiencing a communication error or technical failure, preventing it from operating correctly.
Your boiler's computer system has encountered a logic error and needs to be restarted to clear the fault.
Your boiler's computer system has encountered an internal error and cannot operate correctly.
Your boiler's computer is having a internal memory error that is preventing it from starting up safely.
Your boiler's internal computer is experiencing a temporary processing error that is preventing it from starting up correctly.
Your boiler’s internal computer is experiencing a memory error and cannot safely operate its recovery systems.
Your boiler's computer memory has detected an internal data error, meaning the control system is confused and cannot safely operate the boiler.
Your boiler's internal computer is experiencing a communication error and has decided to shut down to prevent potential damage.
Your boiler's main control computer is experiencing a temporary glitch or internal error, which has caused it to pause its normal operation as a safety precaution.
Your boiler's computer system has encountered an internal error and has temporarily shut itself down to prevent any further issues.
Your boiler's computer is struggling to read internal electronic signals, which has caused it to stop working to ensure safety.
Your boiler's computer system has encountered an internal glitch and needs to be restarted or reset by a professional.
Your boiler's computer is experiencing a temporary software confusion which is preventing it from starting up correctly.
Your boiler is struggling to breathe properly, meaning it cannot safely clear exhaust gases and has shut down to protect your home.
Your boiler is currently heating the water faster than your radiators or taps can use it, causing it to throttle down or pause to prevent overheating.
Your boiler has performed an internal safety test of its electronic controls and is currently waiting for you to restart the system to see if the error clears.
Your boiler is failing to detect a flame, which means it has safely shut itself down to prevent gas from building up.
Your boiler is currently booting up, which is a normal process while it checks its systems before starting to heat your home.
Your boiler has stopped working because it cannot safely start the internal fire that heats your water.
Your boiler is currently stuck in a diagnostic testing mode rather than operating normally to provide heating or hot water.
Your boiler is struggling to push water around your heating system because the internal water pressure is too low or the pump is failing to detect movement.
Your boiler is currently just in the process of lighting the flame to begin heating your water or radiators.
Your boiler is having difficulty communicating with the system that manages the essential mix of gas and air needed for safe ignition.
Your boiler is temporarily pausing to prevent overheating while it manages your hot water supply, which is a normal part of its internal self-regulation.
Your boiler has detected that the flame is still burning even though it has told the gas supply to shut off.
Your boiler's internal computer is failing to communicate correctly with its external controls, preventing your heating or hot water from turning on.
Your boiler has briefly lost power, likely due to a minor power cut or a loose plug connection.
Your boiler is heating up much faster than it should, which has caused it to automatically shut down to prevent potential damage from overheating.
Your boiler is heating the water much faster than it is able to move it away, causing the system to stop as a safety precaution to prevent overheating.
Your boiler has lost its ability to accurately measure the temperature of the water flowing through the heating system because one of its internal sensors is sending a faulty electrical signal.
Your boiler has lost its ability to measure the temperature of the water flowing through the system, so it has purposefully stopped working to prevent overheating.
Your boiler has detected an internal error during its automatic safety check and has locked itself down to prevent operation.
Your boiler has detected an internal software or safety check failure and has shut down to prevent unsafe operation.
Your boiler is struggling because the electricity supply it is receiving is weaker than it needs to operate reliably.
Your boiler is currently running a brief automatic safety check of its internal air and exhaust system before it attempts to fire up.
Your boiler is automatically running a brief maintenance cycle to ensure the internal pump remains free and doesn't get stuck while not in use.
Your boiler's internal computer is struggling to recognise the electronic identification chip that stores its specific settings.
Your boiler's computer is having trouble recognising its own internal settings and requires a professional to reset or replace the electronic control unit.
Your boiler is struggling to confirm that the burner flame has safely extinguished before attempting to restart.
Your boiler has detected that an internal valve responsible for controlling gas flow is not sealing properly, meaning it cannot operate safely.
Your boiler has detected an internal issue where a component responsible for controlling the fuel supply is failing to shut properly, preventing the system from operating safely.
Your boiler's electronic brain is having trouble communicating with the burner, meaning your heating and hot water have stopped working for safety reasons.
Your boiler is failing to detect or trigger the heating process required to provide you with hot water.
Your boiler's electronic control panel is currently unable to communicate with its internal components, meaning the system has safely shut down to prevent incorrect operation.
Your boiler has detected that it is running at the absolute limit of its burning capacity and has shut down to protect itself from overheating.
Your boiler is struggling to detect the flame needed to heat your water and has switched itself off for safety reasons.
Your boiler is simply reminding you that its annual service is now due to keep it running safely and efficiently.
Your boiler has identified that the internal water pump setting is not configured correctly for your specific system model.
Your boiler is having trouble 'talking' to your hot water tank or internal sensor, which means it cannot accurately tell if your water is hot enough.
Your boiler has been running for a very long time without a proper break, likely due to a system management setting or a sensor error, and needs a reset to clear the accumulated timer.
Your boiler is struggling to read the temperature of the water returning to it, so it has safely shut down to prevent overheating.
Your boiler has lost the connection to the sensor that helps keep your hot water ready for fast delivery.
Your boiler has lost the connection to the weather sensor outside your home and is now running on a default setting to ensure you still have heating and hot water.
Your boiler is struggling to accurately read either the outside air temperature or the gas combustion quality, which may prevent it from heating your home efficiently.
Your boiler has stopped working because it cannot correctly detect the temperature of the water inside because of a faulty internal sensor connection.
Your boiler has lost the connection to the sensor that measures how hot the water is inside it, so it has safely shut down to prevent overheating.
Your boiler has detected an electrical fault with the sensor that tracks the temperature of the water inside it, causing it to stop working to stay safe.
Your boiler has lost communication with its internal temperature sensor, so it has safely shut down to prevent overheating.
Your boiler's computer has detected a serious internal processing error that is preventing it from operating safely.
Your boiler has detected an internal software or communication error that is preventing it from operating correctly.
Your boiler's internal computer is experiencing a communication error, meaning it has safely shut itself down to prevent potential issues.
Your boiler's internal computer is experiencing a communication error and has shut down for safety to prevent incorrect operation.
Your boiler is having trouble breathing, meaning it cannot properly clear exhaust gases or draw in fresh air due to a possible blockage or a fan issue.
Your boiler's internal computer has failed to automatically adjust its settings to ensure it burns gas safely and efficiently.
Your boiler is struggling to start the internal fire necessary to produce heat, meaning it has safely shut itself down to prevent gas from building up.
Your boiler is struggling to detect the flame accurately while it tries to set itself up, meaning it cannot safely start your heating or hot water.
Your boiler's internal computer is failing to talk to the part that creates heat, meaning it cannot start up.
Your boiler's air extraction fan is staying on longer than it should after finishing its work, which often points to an electronic communication error inside the unit.
Your boiler has detected a potential issue with the gas flow control system after it has finished running, which may indicate a safety concern.
Your boiler is failing to light the internal flame needed to heat your home's water.
Your boiler has detected an issue with the way it is burning gas and has shut itself down to ensure your safety.
Your boiler is failing to detect a flame, so it has safely shut itself down to prevent gas from escaping.
Your boiler is currently stuck in a diagnostic testing mode used by engineers rather than operating in its normal heating mode.
Your boiler has encountered an internal electronic error that is preventing it from operating correctly.
Your boiler has detected an issue with how the gas supply is being controlled, so it has safely shut itself down to prevent any risk.
Your boiler has detected that it cannot safely communicate with the part that controls the gas flow, so it has shut itself down to keep your home safe.
Your boiler is struggling to control the gas flow needed to heat your home, so it has safely shut itself down to prevent any issues.
Your boiler has detected an issue with the fuel supply control system and has deliberately shut down to stay safe.
Your boiler has stopped working because the flame inside went out while it was trying to heat your water or home.
Your boiler's computer is experiencing a software or internal communication error, meaning it has safely shut down to prevent incorrect operation.
Your boiler's internal computer is experiencing a temporary communication error which has caused the system to stop working as a safety precaution.
Your boiler's internal computer has experienced a temporary glitch or memory error, causing it to stop operating to protect the system.
Your boiler's internal computer is experiencing a communication error, meaning it has safely shut down to prevent incorrect operation.
Your boiler is struggling because it is not receiving the correct amount of electrical power, which is likely due to a poor connection or a minor electrical fault.
Your boiler is struggling to pump enough water through the system, meaning it cannot heat your home or provide hot water effectively.
Your boiler has stopped working because it cannot detect that the internal fan, which is essential for safely venting exhaust gases, is spinning correctly.
Your boiler is struggling to work because the electricity supply it is receiving from your home's wall socket is weaker than it needs to be.
Your boiler is rapidly cycling on and off because it cannot efficiently release the heat it is generating, which often points to a blockage or a bottleneck in your heating system.
Your boiler's internal computer chip has identified that the electronic component containing its specific configuration settings is either incorrect or not properly connected.
Your boiler's computer chip is not communicating correctly with the main control board, which is preventing the system from starting up safely.
Your boiler has attempted to ignite but failed to keep its flame burning at the required low intensity, so it has shut down as a safety precaution.
Your boiler is trying to start but the flame is failing to establish, so it has safely shut itself down to prevent gas from building up.
Your boiler has failed to light the flame, which means it cannot produce any heating or hot water for your home.
Your boiler is trying to stay lit but keeps failing, which means it has automatically shut down to keep your home safe.
Your boiler is having trouble confirming that the gas flame is lit properly and has stopped working as a safety precaution.
Your boiler has attempted to start but failed to detect a flame, meaning it cannot produce heat or hot water.
Your boiler has attempted to ignite several times but is failing to stay lit, meaning you currently have no heating or hot water.
Your boiler has detected that its internal settings do not match the way your heating system is physically set up, meaning it cannot safely start until these are corrected.
Your boiler has detected a configuration setting that does not match the way your heating system is physically connected, preventing it from starting up correctly.
Your boiler's internal computer is experiencing a software glitch or communication error that is preventing the burner from igniting safely.
Your boiler's main control computer is experiencing a temporary brain freeze and cannot communicate properly with the rest of the unit.
Your boiler's main control computer is experiencing a software or internal communication error, meaning the system has safely shut itself down to prevent further issues.
Your boiler's main computer is having an internal communication error and cannot operate safely.
Your boiler has detected that the internal fan responsible for safely venting exhaust gases is not responding, so it has shut down to prevent unsafe operation.
Your boiler has stopped working because it cannot move the air and exhaust gases through the system properly.
Your boiler has detected an incorrect temperature reading, which has caused it to shut down for safety reasons to prevent overheating.
Your boiler has detected that water is not flowing through it fast enough to keep it cool, so it has stopped working as a safety precaution.
Your boiler has detected that the water inside the unit is getting too hot and has automatically shut down to prevent damage.
Your boiler has detected that the water inside it is heating up much faster than it safely should, causing the system to shut down to prevent damage.
Your boiler has detected that the water is not heating up evenly, which means it will stop working to protect itself from internal damage.
Your boiler has stopped working because the water pressure inside your heating system has dropped below the required level.
Your boiler has detected that the electricity supply coming from your mains is weaker than required to operate safely.
Your boiler's internal computer is experiencing a communication error, meaning the system cannot safely operate your heating or hot water.
Your boiler has detected an internal software or processing error that is preventing it from operating correctly.
Your boiler has detected a critical internal error and has shut itself down as a safety precaution, meaning you currently have no heating or hot water.
Your boiler is having trouble communicating with its wireless thermostat, which is preventing it from knowing when to turn the heating on.
Your boiler is currently unable to accurately measure the temperature of the water it is heating, so it has stopped providing hot water to keep your system safe.
Your boiler's internal control system has lost its digital connection, meaning it cannot properly send or receive instructions to run your heating or hot water.
Your boiler's main brain is unable to communicate with its internal control unit, which means the system has stopped working to protect itself.
Your boiler's computer is struggling to read its internal configuration settings, which is preventing it from starting up correctly.
Your boiler is overheating because it cannot move the hot water away from the heating unit quickly enough, or it is struggling to accurately read its own temperature.
Your boiler is failing to ignite because it is not receiving the signal or power required to safely turn on.
Your boiler's fan unit, which clears out exhaust gases, has failed to start, so the system has safely shut down to prevent unsafe operation.
Your boiler's internal air blower is struggling to run at the correct speed, which is preventing the system from safely igniting your heating and hot water.
Your boiler is struggling to shut down its internal ventilation system properly, which means it cannot safely restart or regulate itself.
Your boiler has detected that the internal ventilation fan is spinning faster than it should, which has caused it to shut down for safety reasons.
Your boiler is struggling to accurately measure the temperature of the water returning to it, which causes it to stop working to protect the system from overheating.
Your boiler is failing to detect a request for heat from your thermostat or internal timer, likely due to a loose wire or a disconnected control link.
Your boiler has lost its ability to accurately measure the water temperature, so it has safely shut itself down to prevent overheating.
Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent any damage or danger.
Your boiler has failed to light the flame, which means it has stopped working to keep you safe.
Your boiler's computer system has encountered a general internal communication issue that is preventing it from operating correctly.
Your boiler has detected a flame signal when it shouldn't be running, which is a safety concern that requires immediate professional attention.
Your boiler has detected that a flame is still burning inside, even though it has sent a signal to turn the gas off, which indicates a serious safety monitoring fault.
Your boiler's reset button has been held down for too long, causing the system to enter a settings mode that prevents it from firing.
Your boiler is failing to light the flame or keep it running, which means it cannot provide you with heating or hot water until the ignition system is serviced.
Your boiler is working exactly as it should and there is nothing to worry about.
Your boiler is not burning fuel correctly, which is causing soot buildup and potential safety issues with the exhaust gases.
Your boiler is failing to light because the internal component responsible for sparking the flame is not positioned correctly.
Your boiler is not mixing air and fuel correctly for combustion, which could lead to unsafe operation if left unresolved.
Your boiler is struggling to stay lit reliably, causing it to shut down periodically for safety reasons.
Your boiler has stopped working because it cannot safely ignite or maintain its internal flame.
Your boiler has completely lost power and is not responding, meaning it cannot provide any heating or hot water until the electrical supply is restored.
Your boiler is failing to light because the fuel supply is interrupted, blocked, or not reaching the burner as it should.
Your boiler is making unusual rattling or grinding noises, which usually suggests there is trapped air in the system or a internal mechanical part is starting to wear out.
Your boiler is leaking fuel or failing to burn it correctly, which is releasing hazardous fumes into your home.
Your boiler is currently unable to start up because a small protective electrical fuse inside the unit has blown, cutting power to internal systems.
Your boiler is simply performing a routine startup check and will be ready to use in a few moments.
Your boiler has detected a general internal technical fault that prevents it from operating correctly.
Your boiler is currently unable to start because an internal protective fuse has blown and will need to be replaced by a professional.
Your boiler is struggling to power its internal control systems due to a blown electrical fuse, meaning it cannot start up correctly.
Your boiler is struggling to breathe properly during startup, which prevents it from igniting smoothly and safely.
Your boiler has stopped circulating water, meaning it cannot provide heating or hot water, and the system is currently unable to operate.
Your boiler is rapidly turning itself on and off because it cannot efficiently heat the water circulating through your radiators.
BoilerFaultCodes