67 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Condens 7000 WP
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 computer parts are not communicating correctly because they appear to be mismatched or incompatible with each other.
Your boiler's computer or its security identity chip has failed, meaning the system cannot safely start the burner.
Your boiler is operating normally and is currently providing heat to your radiators.
Your boiler is simply letting you know that it is currently busy heating up your tap water and is working as expected.
Your boiler is currently in a normal waiting phase because the heating or hot water controls have signalled that it is about to start running.
Your boiler is currently sitting in standby mode because it has reached its target temperature and is waiting for a new request for heating or hot water.
Your boiler is currently taking a short break because it has reached its target temperature and is waiting for the water to cool down slightly before firing up again.
Your boiler is currently running at a fixed power level for testing purposes and is not responding to your normal thermostat settings.
Your boiler is overheating because the water inside is heating up faster than it can be moved around the system.
Your boiler has entered a temporary lock-out mode because a service engineer's diagnostic tool was recently plugged in and has not been properly disconnected or reset.
Your boiler’s internal control parts are speaking different languages because a newer component has been installed that is incompatible with the older system.
Your boiler has started up but cannot detect the water getting any hotter, so it has shut down to prevent overheating.
Your boiler is temporarily reducing its power because it is producing more heat than your radiators can currently take away.
Your boiler is currently running a self-diagnostic check and is not experiencing an actual fault.
Your boiler is currently increasing its power to meet the demand for heating or hot water, which is a normal operational activity rather than a system failure.
Your boiler is currently going through its normal startup sequence and is getting ready to light the flame.
Your boiler has stopped working because it has detected an electrical issue with the internal gas valve or its wiring.
Your boiler is currently focused on providing hot water to your taps and will return to heating your radiators once you turn the hot water off.
Your boiler's internal computer chips are not communicating correctly because an incorrect or incompatible part has been installed.
Your boiler has detected an electrical fault with the sensor that monitors exhaust gases, causing the system to shut down for safety.
Your boiler's internal computer or its identification chip has developed a communication failure, preventing the system from operating.
Your boiler has stopped working because the internal fan, which is needed to safely clear waste gases, has either lost power or stopped communicating with the main control board.
Your boiler is performing a routine safety self-check and will restart automatically in a few minutes.
Your boiler has shut down because the internal fan is spinning faster than the system can safely control.
Your boiler has stopped working because the internal fan is spinning too slowly to safely clear away exhaust fumes.
Your boiler's air fan is failing to start up, which means the system cannot safely clear the combustion chamber to begin the heating process.
Your boiler's fan is failing to spin at the correct speed to begin the ignition process, preventing the boiler from firing up.
Your boiler has stopped working because there is not enough water pressure in the system to operate safely.
Your boiler has stopped working because it cannot detect any water being moved through the system by the internal pump.
Your boiler has detected an electrical fault with the internal sensor that monitors the water returning to the unit, causing it to shut down to prevent damage.
Your boiler has lost its connection to the sensor that monitors the water returning to the unit, causing it to stop working for safety.
A safety switch or an external control, such as a thermostat or a condensate pump, has tripped and told the boiler to stop running.
Your boiler is heating up too quickly, which usually means the water inside is not circulating properly or the system is low on pressure.
Your boiler has detected that the water is heating up too quickly or isn't circulating properly, causing it to shut down to prevent overheating.
Your boiler has shut down because it thinks the water returning to the unit is dangerously hot, which usually means water isn't circulating through your radiators properly.
Your boiler has stopped working because its internal thermometer has developed an electrical fault and can no longer tell how hot the water is.
Your boiler has lost connection with a internal sensor that monitors water temperature, meaning it cannot safely heat your home until the connection is restored.
Your boiler has sensed that the internal water temperature has become dangerously hot, causing it to shut down for safety.
Your boiler has shut down because it is detecting dangerously high temperatures in the exhaust flue or a fault with the safety sensor itself.
Your boiler has reached an unsafe temperature and has automatically shut down to prevent damage or overheating.
Your boiler has detected an unsafe level of heat or an electrical fault in its safety sensor and has locked down to prevent damage.
Your boiler has shut down because a safety sensor has detected that the system is overheating or the sensor itself has a loose connection.
Your boiler has shut down because it has detected internal water temperatures that are dangerously high, indicating the system is overheating.
Your boiler has shut down because it has detected internal water temperatures that are dangerously high, likely due to a circulation or sensor issue.
Your boiler has shut down because it thinks the water returning to the unit is dangerously hot, which usually means water isn't circulating properly through your radiators.
Your boiler has detected that the connection to the sensor monitoring exhaust fumes has been broken or lost, causing the system to shut down for safety.
Your boiler is failing to detect a flame after it starts up, causing it to shut down for safety.
Your boiler has lost its flame while running because it cannot detect a steady signal that the gas is burning correctly.
Your boiler has lost its connection to the gas valve, meaning it cannot light the flame to provide heating or hot water.
Your boiler's computer brain has developed a fault and can no longer safely control the burner to heat your home.
Your boiler is trying to light itself for too long without successfully sensing a flame, so it has shut down for safety.
Your boiler's computer system has detected an internal electronic fault, preventing the heating and hot water from starting up.
Your boiler's computer brain has developed a serious internal fault or a loose connection, preventing it from starting the burner safely.
Your boiler's internal computer memory chip has developed a fault, preventing the system from identifying itself and operating safely.
Your boiler’s internal computer chip has encountered a communication error or technical failure, preventing the system from starting up.
Your boiler has stopped working because its internal computer has detected a problem with the sensors that monitor its performance.
Your boiler's main internal computer has developed a serious internal fault and cannot safely manage the burner.
Your boiler's main internal computer has developed a serious fault and is unable to safely control the flame.
Your boiler's internal computer has encountered a communication error or a hardware failure, preventing it from safely starting the burner.
Your boiler's main computer brain or internal identity module has suffered a critical failure and cannot communicate correctly.
Your boiler has detected a flame signal even though it hasn't started the burner yet, which is causing it to shut down for safety.
Your boiler has experienced a brief interruption to its electrical power supply and needs to be restarted.
Your boiler detects a flame signal even though it has commanded the burner to turn off, which may be due to a faulty sensor or a sticking gas valve.
Your boiler has shut down because it lost power while it was already trying to deal with an internal safety error.
Your boiler has detected that the water pressure in the system is too low, causing it to reduce its output or stop working to prevent damage.
Your boiler is experiencing a critical control system failure that causes it to shut down and attempt to restart itself repeatedly.
Your boiler is undergoing a system reset, which means it is attempting to restart itself after detecting an internal error or interruption.
BoilerFaultCodes