46 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: ThemaFast
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 stopped working because it cannot move the hot water around your house, so it has locked itself for safety.
Your boiler has detected that waste water cannot drain away properly, likely due to a blockage or frozen external pipe, causing it to shut down for safety.
Your boiler has detected a signal suggesting a flame exists when it is actually turned off, which is a safety concern that prevents it from starting to avoid a potential gas buildup.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler has shut down because it has detected that the water inside it has become dangerously overheated.
Your boiler has detected that the water returning from your radiators is dangerously hot, causing the system to shut down to prevent damage.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
Your boiler is failing to light the internal flame, which means it cannot produce any heat or hot water.
Your boiler is shutting down because it senses the water is heating up far too quickly for it to be safe or normal.
Your boiler has stopped working because the mechanical fan that pushes waste gases outside is not spinning or responding properly.
Your boiler has detected that the internal mechanism responsible for safely venting exhaust gases has stopped working, so it has shut down to keep your home safe.
Your boiler is failing to ignite because it cannot detect that a flame has successfully started.
Your boiler's electronic brain has encountered an internal error and has stopped working as a safety precaution.
Your boiler has lost its electrical power supply, which could be due to a power cut in your home or a tripped fuse.
Your boiler has lost its connection to the electrical power supply and cannot function until power is restored.
Your boiler's internal computer has encountered a critical error and can no longer safely operate the heating or hot water systems.
Your boiler has detected an internal computer error that is preventing it from starting up correctly.
Your boiler's computer is experiencing an internal error, meaning the system is unable to safely manage its own operation, so it has shut down to prevent damage.
Your boiler is failing to start because it cannot confirm that the internal fan is moving air correctly to vent exhaust gases safely.
Your boiler is failing to start because it cannot confirm that the exhaust fan is effectively clearing the air inside the unit.
Your boiler has sensed that the water inside is heating up far too quickly and has turned itself off to prevent overheating.
Your boiler has temporarily paused because it has detected a large temperature difference between the water leaving the boiler and the water returning to it, suggesting a blockage or poor circulation.
Your boiler's computer system has encountered an internal error and cannot safely operate your heating or hot water, meaning the unit has shut down.
Your boiler's internal computer has encountered a critical error and can no longer safely operate.
Your boiler's main electronic brain has encountered an internal error and has shut down to prevent further damage.
Your boiler's main computer brain is experiencing an internal error, preventing the system from starting up or operating correctly.
Your boiler's computer system has encountered an internal error and cannot communicate properly to keep the unit running.
Your boiler's internal computer has encountered a critical electronic error that is preventing it from functioning safely.
Your boiler's temperature sensors have been swapped during a recent repair or installation, causing the system to misread the water flow.
Your boiler's temperature sensors have been wired incorrectly, preventing the system from accurately measuring how hot the water is.
Your boiler's computer is experiencing an internal error, which means it has safely shut itself down and stopped working.
Your boiler has detected that the water inside the system is not circulating properly, causing an abnormal temperature difference between where it leaves and returns to the unit.
Your boiler has detected that the water inside is not circulating properly, causing an unusual temperature gap between the outgoing and incoming pipes.
Your boiler has stopped working because a sensor that measures the temperature of the water being sent to your radiators is sending an incorrect electrical signal.
Your boiler has detected an electrical fault with one of its temperature sensors, meaning it cannot accurately measure the heat inside the system and has stopped working as a safety precaution.
Your boiler is struggling because a temperature sensor in the water pipe has stopped working correctly, causing the system to shut down for safety.
Your boiler is struggling to read its own temperature because an internal sensor is giving an incorrect signal, so it has shut down to protect the system.
Your boiler's temperature sensor is failing to provide an accurate reading to the system, causing the unit to shut down to prevent overheating.
Your boiler's temperature sensor is failing to provide a clear reading, so the system has shut down to prevent overheating.
Your boiler is struggling to accurately measure the temperature of the water returning to it, which causes it to shut down for safety.
Your boiler is having trouble measuring the temperature of the water returning from your radiators, which prevents it from heating your home correctly.
Your boiler's internal computer has encountered a critical error and is unable to communicate with its own systems, causing the unit to shut down for safety.
Your boiler's electronic command center has encountered a serious internal error and has stopped working to prevent further damage.
Your boiler's internal computer has encountered a critical error and can no longer safely operate.
Your boiler's internal computer has encountered a serious error and is unable to operate safely, meaning your heating and hot water will not work.
Your boiler's internal computer is experiencing a software or communication error and needs an expert to reset or replace it.
BoilerFaultCodes