Baxi 400 424 / 428 Combi Fault codes & diagnostics

Your boiler has lost its connection to a sensor that monitors the temperature of the water returning to the unit, causing it to stop working for safety reasons.

Your boiler has detected a faulty reading from a temperature sensor, which has caused it to stop working for your safety.

Your boiler is repeatedly struggling to keep its flame lit while it tries to heat your home or water.

Your boiler is struggling to push air through its system correctly, so it has safely shut itself down to prevent any unsafe operation.

Your boiler has detected that the water returning to the system is hotter than the water leaving it, which indicates a circulation issue that is causing it to shut down to prevent damage.

Your boiler has detected that water is not flowing around your heating system as it should, so it has shut down to prevent internal overheating.

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

Your boiler's internal control computer is failing to communicate properly, which has caused it to shut down for safety.

Your boiler has stopped working because its internal computer can no longer talk to the part that controls the gas supply.

Your boiler's internal computer is struggling to identify its specific configuration because a small electrical connector inside has been moved or become loose.

Your boiler's internal computer has detected a change in its configuration settings, which is preventing it from starting up correctly.

Your boiler has detected an incorrect internal setting or a communication error between its internal components, causing it to shut down for safety.

Your boiler is struggling to communicate with an external add-on, such as a smart thermostat or a weather compensation sensor, preventing it from starting correctly.

Your boiler is unable to safely control the flow of gas needed to ignite and heat your water, so it has shut itself down as a safety precaution.

Your boiler has stopped working because a sensor that monitors the water temperature has developed a wiring or electrical fault.

Your boiler has lost the ability to measure the temperature of the water inside it, so it has safely shut down to prevent overheating.

Your boiler has detected that the water inside it has become dangerously hot and has shut itself down to prevent damage or overheating.

Your boiler has detected an issue with the sensor that monitors the temperature of the exhaust gases, causing it to shut down for safety.

Your boiler has detected a disconnection in the sensor that monitors the temperature of the gases leaving your home, which is causing it to stop working as a safety precaution.

Your boiler has detected that it is overheating and has automatically shut down to prevent internal damage.

Your boiler has tried and failed to light the flame five times in a row, so it has locked itself out for safety.

Your boiler has stopped working because the fan, which clears exhaust gases, is physically stuck or unable to spin properly.

Your boiler is failing to ignite because it is unable to properly control the supply of gas needed to create a flame.

Your boiler has lost the electronic connection needed to control the gas supply, meaning it has safely shut down to prevent any issues.

Your boiler has detected that the water leaving the boiler is much hotter than the water returning to it, suggesting a blockage or a pump issue is stopping the heat from circulating properly.

Your boiler has detected that the water temperature is rising much faster than expected, so it has safely shut itself down to prevent overheating.

Your boiler has detected that the water inside the system is getting much hotter than it should be, so it has shut itself down to prevent damage.

Your boiler has detected that water is not moving through the system properly, which means it has safely shut itself down to prevent overheating.

Your boiler has detected that the water it is trying to heat for your taps is getting hot much faster than it should, causing it to shut down for safety.

Your boiler has lost its internal configuration settings and needs to be reprogrammed by a professional to function again.

Your boiler has lost its specific operational settings, which means it doesn't know how to correctly communicate with its internal control board.

Your boiler's computer has detected an internal configuration error, meaning it has lost the correct settings needed to operate your heating and hot water.

Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.

Your boiler is having trouble 'talking' to one of its internal safety sensors, so it has stopped working to keep your home safe.

Your boiler's control panel has lost its connection to the internal computer, meaning it can no longer send or receive instructions.

Your boiler is trying to start but cannot detect a flame, meaning it will currently provide no hot water or heating.