61 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Baxi 600 or 800 Series
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Tap any card for details
Your boiler's internal memory has encountered a configuration error and needs to be reset or reprogrammed by a professional.
Your boiler has temporarily shut down because the water inside it has become dangerously hot.
Your boiler has detected that the water inside is heating up far too quickly, which usually happens when water isn't flowing through the system properly.
Your boiler is temporarily shutting down because the water getting hot inside is not circulating away fast enough, causing a dangerous temperature gap.
Your boiler has temporarily stopped working because a safety shutdown switch has been triggered.
Your boiler has temporarily stopped working because it has detected an external safety shutdown signal or a potential freezing risk.
Your boiler's main control panel has temporarily lost its connection with the internal computer, meaning it cannot receive your commands for heating or hot water.
Your boiler has temporarily lost its ability to talk to its internal main control board, which stops the system from operating safely.
Your boiler has detected that the incoming gas supply pressure is too low to operate safely and effectively.
Your boiler's computer system has lost its settings and needs to be properly reconfigured by a professional.
Your boiler's internal computer system has lost its correct settings and needs a professional to reprogram it.
Your boiler's main electronic brain cannot recognise the power supply unit, meaning it has temporarily stopped working for safety reasons.
Your boiler's internal computer has lost its correct settings and needs a professional to reprogram it.
Your boiler is currently in setup mode, which usually happens after a new part has been installed or the settings have been reset.
Your boiler's internal computer parts have temporarily lost the ability to talk to each other properly.
Your boiler has stopped working because the flame has unexpectedly gone out while trying to heat your home.
Your boiler has detected an internal issue with its core operating system, so it has safely shut down to prevent any risk.
Your boiler is reminding you that it is due for its regular annual service to keep it running safely and efficiently.
Your boiler has stopped working because something is blocking either the internal pipework or the pipe that takes away waste water outside.
Your boiler has temporarily shut down because a safety device or external control has triggered a stop signal.
Your boiler has lost its connection due to a blockage, which has temporarily stopped it from working.
Your boiler is experiencing an internal computer memory error and needs to be reset or reprogrammed by a professional.
Your boiler has experienced a memory or data settings error, meaning its internal computer has lost or corrupted its configuration.
Your boiler has temporarily stopped working because it is having trouble reading its own water temperature correctly.
Your boiler has temporarily stopped working because it cannot accurately read the water temperature inside the system.
Your boiler has temporarily stopped working because it is getting incorrect temperature readings from its internal sensors.
Your boiler has temporarily stopped working because it is having trouble reading the temperature of the water correctly.
Your boiler has temporarily stopped working because it cannot accurately read the water temperature inside the system.
Your boiler has temporarily stopped working because it cannot accurately read the water temperature inside the system.
Your boiler has temporarily stopped working because it is having trouble reading the correct water temperature.
Your boiler has detected an issue with its internal temperature monitoring, so it has safely shut down to prevent overheating.
Your boiler has temporarily stopped working because the water inside is not circulating properly between the heating pipes.
Your boiler has temporarily stopped working because it cannot accurately read the water temperature inside the system.
Your boiler has temporarily shut down because the main internal component has become too hot, which safely prevents damage.
Your boiler is trying to fire up for heating or hot water, but the burner is failing to ignite successfully.
Your boiler is temporarily locked out because it is detecting a flame inside when it shouldn't be.
Your boiler has detected an issue with the valve that controls the gas supply, meaning it has safely shut down to prevent any risk.
Your boiler has stopped working because the internal fan that safely removes waste gases is not running properly.
Your boiler has temporarily stopped working because it has detected an incorrect temperature reading or a problem with water flow inside the system.
Your boiler has tried to start up several times but failed to ignite the flame, so it has locked itself out for safety.
Your boiler's internal computer parts are having trouble talking to each other, which temporarily stops the heating from working properly.
Your boiler has temporarily lost its ability to talk to its internal computer system, causing it to shut down for safety.
Your boiler has safely shut itself down and locked out due to a safety interlock or external device signaling a fault.
Your boiler has detected an internal communication or testing error with its secondary heat recovery or control unit.
Your boiler has automatically shut down because the main internal components have become dangerously hot.
Your boiler has temporarily stopped working because it cannot accurately read the water temperature inside the system.
Your boiler has automatically shut down because the main internal components became dangerously hot.
Your boiler has failed to light after multiple attempts, meaning you currently have no heating or hot water.
Your boiler has stopped working because the internal fan that safely clears combustion gases is not operating correctly.
Your boiler has experienced a memory or configuration glitch, meaning it has temporarily forgotten how to operate correctly.
Your boiler has registered an unspecified internal system error and requires professional attention to diagnose the exact cause.
Your boiler has detected an issue with the internal fan that safely expels harmful gases outside your home, so it has temporarily stopped working to keep you safe.
Your boiler has temporarily stopped because it cannot detect a flame, likely due to a blockage in the flue or air supply.
Your boiler has failed to light its flame, meaning it cannot provide you with heating or hot water at the moment.
Your boiler has detected a blockage somewhere in its system, which is stopping it from working properly to protect itself from damage.
Your boiler has automatically shut down because the internal water temperature has climbed dangerously high.
Your boiler has detected a blockage in the system, which is stopping it from working properly.
Your boiler is undergoing a system reset or software reinitialisation, which usually happens automatically after a power interruption or minor system hiccup.
Your boiler is currently processing a manual or automatic system reset to clear a previous error and restart its safety checks.
Your boiler has detected an issue with one of its internal temperature sensors, which means it cannot accurately monitor the water heat and has safely shut down to prevent damage.
Your boiler has temporarily stopped working because it has detected a blockage restricting the flow of water inside the system.
BoilerFaultCodes