Worcester Bosch Greenstar 12i System Fault codes & diagnostics

Your boiler has encountered a general error and needs to be restarted to see if the system can clear the fault itself.

Your boiler has failed to start up or stay lit and has safely switched itself off to prevent any issues.

Your boiler has detected that it is getting too hot too often and has locked itself down as a safety precaution to prevent damage.

Your boiler's computer module does not match the specific model of your unit, preventing the system from starting up or operating correctly.

Your boiler's computer is reporting that an incompatible or incorrect internal control part has been installed, preventing it from functioning correctly.

Your boiler's main control unit has encountered a communication error and is unable to operate safely.

Your boiler's computer system is failing to communicate correctly, which has caused the unit to shut down for safety.

Your boiler's internal computer is failing to communicate with its memory chip, meaning it cannot start because it has forgotten its specific configuration settings.

Your boiler is failing to light the flame properly and has safely locked itself out to prevent a gas build-up.

Your boiler has detected that the internal fan is not moving air correctly, so it has safely shut down to prevent unsafe operation.

Your boiler is struggling to detect water moving through the system, which prevents it from heating your home safely.

Your boiler's internal computer has crashed and needs to be restarted to resume normal operation.

Your boiler is failing to ignite because it cannot detect a flame, meaning your heating and hot water will not work until it is fixed.

Your boiler has detected that the water inside is not circulating correctly, so it has safely shut down to prevent internal overheating.

Your boiler has detected an internal software or communication error that is preventing it from starting up correctly.

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

Your boiler's computer has detected that one of its internal sensors is sending back confusing or missing information, so it has shut down as a precaution to prevent system errors.

Your boiler’s computer is struggling to read internal electrical signals, which is preventing it from safely starting up.

Your boiler is struggling because the internal water pump is either jammed or trapped air is preventing it from circulating water properly to your radiators.

Your boiler has detected that the water pump responsible for circulating heat around your home has stopped working or is failing to provide a signal.

Your boiler has detected that the water returning to it is dangerously hot, causing it to shut down to prevent damage.

Your boiler has detected an electrical issue with the part that monitors the flame, preventing it from starting safely.

Your boiler is struggling to accurately measure its internal water levels because a wire has likely come loose or a small electronic sensor has failed.

Your boiler's control system has lost its ability to read the water pressure, causing it to stop operating to ensure safety.

Your boiler's internal computer is struggling to read its own sensors, which has caused it to shut down for safety to prevent incorrect heating operations.

Your boiler has detected a false flame signal even though it has switched off, so it has safely locked itself to prevent starting again.

Your boiler has detected that the exhaust gases are getting too hot and has safely switched itself off to prevent damage.

Your boiler has detected an electrical fault in the sensor that monitors exhaust gases, so it has safely shut down to prevent incorrect operation.

Your boiler has detected that a key safety sensor has lost its connection, so it has safely shut itself down to prevent operation without proper monitoring.

Your boiler is struggling to talk to its internal control system, which means it has stopped working to prevent any potential operating errors.

Your boiler's computer is struggling to get a steady power supply from your home's electricity, causing it to stop work to protect its internal parts.

Your boiler is struggling to circulate water, likely because the internal pump is jammed or there is air trapped inside the system.

Your boiler is struggling to circulate water because the internal pump is either jammed or not receiving enough water to function correctly.

Your boiler is struggling to move water around your heating system, which means it has stopped working to prevent itself from overheating.

Your boiler has detected an issue with the sensor that monitors exhaust gases, so it has safely shut down to prevent incorrect operation.

Your boiler's internal computer has lost contact with the main control panel, preventing it from starting up correctly.

Your boiler's main control board has lost communication with an internal plug-in module or sensor, meaning it cannot currently operate.

Your boiler's main internal computer cannot find its unique identity chip, causing the system to stop working for safety.

Your boiler's computer has detected a serious internal fault that prevents it from operating safely, requiring a qualified professional to inspect or replace the electronic control system.

Your boiler's internal computer is malfunctioning and cannot communicate with the rest of the unit to operate your heating or hot water.

Your boiler's computer has encountered an internal communication error and has safely shut itself down to prevent potential issues.

Your boiler's internal fan isn't spinning fast enough to safely clear away exhaust fumes, causing the system to shut down for your protection.

Your boiler has detected that air is not flowing through the system correctly, which is preventing it from running safely.

Your boiler has detected that the internal fan is spinning too slowly to safely clear waste gases, so it has shut down as a precaution.

Your boiler has detected that its internal air fan has been running non-stop for a full day, which is preventing the system from heating correctly.

Your boiler's internal fan is spinning faster than it should, which has caused the system to shut down for safety.

Your boiler has detected that the internal exhaust fan is spinning faster than it should, which is preventing the system from starting safely.

Your boiler has stopped working because the internal component responsible for pushing air through the system is failing to start.

Your boiler's internal air intake system is failing to start, which prevents the unit from igniting to provide heating or hot water.

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

Your boiler has lost communication with the device that tells it how much water is inside, so it has shut down to prevent damage.

Your boiler is struggling because it cannot accurately tell how hot the water is as it flows back into the system.

Your boiler has lost its connection to an essential safety internal plug, meaning it currently cannot communicate correctly with its control system.

Your boiler has detected that the water inside the unit is getting too hot compared to the water travelling to your radiators, causing it to shut down to prevent damage.

Your boiler has detected a fault with the internal sensor that monitors the temperature of the water heading to your radiators, causing the system to shut down for safety.

Your boiler has detected an electrical fault with the internal sensor that monitors the flow of water, meaning it cannot safely regulate the temperature and has shut down to prevent damage.

Your boiler has detected that hot water is flowing in the wrong direction or circulating incorrectly, meaning it cannot heat your home properly.

Your boiler is having trouble 'reading' the temperature of the incoming water, which is causing it to stop operating correctly to prevent a potential error.

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 the water inside the unit is getting too hot, so it has safely shut itself down to prevent any damage.

Your boiler has sensed that it is getting dangerously hot and has shut itself down to prevent damage or overheating.

Your boiler has detected that it is running too hot or that the exhaust system is blocked, so it has safely shut itself down to prevent damage.

Your boiler has detected that it is running much too hot and has automatically shut itself down to prevent any damage or safety issues.

Your boiler has tried to light several times but has been unable to detect a flame, causing the system to shut down for safety.

Your boiler has attempted to start but could not detect a flame, causing it to shut down for safety reasons.

Your boiler has tried to start four times but failed to light, so it has shut down as a safety precaution.

Your boiler has detected that the exhaust gases are getting too hot, too quickly, so it has turned itself off to prevent internal damage.

Your boiler has detected that hot gases are building up inside the system while the water meant to be heating your home is staying cold, so it has safely shut down to prevent overheating.

Your boiler has detected that the water inside isn't warming up as expected after it fires up, so it has stopped trying to prevent potential damage.

Your boiler has detected that it cannot move water through your radiators or pipes fast enough, causing the internal temperature to rise dangerously high.

Your boiler's internal computer has encountered a software or electronic error and can no longer control the heating properly.

Your boiler thinks it can still see a flame inside even though it has been told to turn off, which is a safety conflict that prevents it from starting up again.

Your boiler has detected that the water pump is not running as expected, which prevents heat from circulating through your home.

Your boiler has failed to light the flame after five consecutive attempts and has shut itself down as a safety precaution.

Your boiler is failing to communicate with your thermostat or timer, preventing it from turning on when it should.