BoilerFaultCodes.com

Worcester Bosch CDi Classic Fault Codes

Regular Natural GasLPG 30-40 kW 2012-2019 Discontinued
GC Numbers: 41-406-3141-406-3241-406-3341-406-3441-406-35

Replaced by: Greenstar 8000 Life

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Most common fault codes

9U233
Your boiler's main internal computer or memory chip has developed a communication fault or has failed, meaning the unit cannot safely control the heating process.
Gas Safe engineer required · £250-£450
235
Your boiler's internal computer parts are unable to communicate with each other due to a software mismatch.
Gas Safe engineer required · £180-450
328
Your boiler has detected an issue with the quality of the electricity supply coming into your home, meaning it cannot operate safely.
Gas Safe engineer required · £250-550

All 50 fault codes

Code Severity Plain English
9U233 High Your boiler's main internal computer or memory chip has developed a communication fault or has failed, meaning the unit cannot safely control the heating process.
226 Low Your boiler has logged a note that a technician's diagnostic tool was plugged in while viewing the error history, but this itself is not a functional breakdown.
235 High Your boiler's internal computer parts are unable to communicate with each other due to a software mismatch.
328 High Your boiler has detected an issue with the quality of the electricity supply coming into your home, meaning it cannot operate safely.
356 High Your boiler is not receiving enough electrical power from the main supply to operate safely and has shut down as a precaution.
360 High Your boiler's computer chip has failed or is recognized as incorrect, meaning the main brain of the boiler cannot talk to its control board.
A1281 High Your boiler is struggling to move water through the system, either because the pump is jammed or there is not enough water present.
A8362 High Your boiler is struggling to operate because the electrical power reaching it is unstable, insufficient, or the control module has failed to recognize the incoming voltage.
B1 High Your boiler’s internal computer chip has lost connection with the main control board, meaning the system cannot identify which model it is and has stopped working for safety.
B7257 High Your boiler's internal computer has developed a fault and can no longer communicate with the main control system.
C6 High Your boiler has stopped working because the internal fan that clears away waste gases is not spinning fast enough to operate safely.
C1264 High Your boiler's fan has unexpectedly stopped working while the unit was running, causing the system to shut down for safety.
C4237 High Your boiler's main internal computer has developed a serious electronic fault and can no longer control the heating process safely.
C4273 High Your boiler has stopped working because the internal fan has been running non-stop for too long, causing the system to shut down for safety.
C6215 High Your boiler has detected that the internal fan is spinning faster than it should, which has caused the system to shut down for safety.
C7214 High Your boiler's fan is failing to start up, which means the system cannot safely clear waste gases and will not allow the boiler to ignite.
C7216 High Your boiler has stopped working because the fan that clears exhaust gases is not spinning at the correct speed.
C7217 High Your boiler has shut down because the internal fan, which safely clears waste gases, has stopped spinning while the boiler was running.
CC800 Low Your boiler has lost communication with its outdoor temperature sensor, meaning it won't be able to adjust its energy use based on the weather outside.
D4341 High Your boiler is overheating because water is not moving through the system quickly enough to carry the heat away.
E2 High Your boiler's internal temperature sensor is failing to provide a correct reading, preventing the heating from starting up safely.
E9 High Your boiler has shut down because it has detected an unsafe build-up of heat or a lack of water circulation within the internal system.
E2222 High Your boiler has detected an electrical fault with the internal sensor that monitors the temperature of the water leaving the unit, preventing it from heating up safely.
E2233 High Your boiler has lost communication with the internal thermometer that monitors water temperature, causing the system to shut down for safety.
E2350 High Your boiler has detected a fault with the sensor that monitors the water temperature leaving the unit, causing it to shut down for safety.
E2351 High Your boiler has lost its connection to the component that monitors water temperature, meaning it cannot safely heat your home or water until the connection is restored.
E9224 High Your boiler has overheated, prompting a safety sensor to shut the system down to prevent damage.
E9276 High Your boiler has shut down because the water inside it has become dangerously hot.
EA High Your boiler is failing to light the flame needed to heat your water or radiators, causing the system to shut down for safety.
EA227 High Your boiler is failing to detect a flame when it tries to start, which means it will not provide any heating or hot water until the issue is resolved.
EA229 High Your boiler has lost its flame suddenly while it was running, causing it to stop heating your home for safety.
EA261 High Your boiler's internal computer brain has encountered a communication error and is preventing the system from starting for safety.
EH258 High Your boiler's internal computer or control module has developed a fault and can no longer communicate with the rest of the system.
F0 High Your boiler's internal computer has encountered a glitch or a hardware failure and can no longer communicate with the rest of the system.
F7 Emergency Your boiler thinks it can still see a flame inside even though it has been told to turn off.
F0238 High Your boiler has detected an internal electrical problem with the component that controls the gas supply, causing the system to shut down for safety.
F0239 High Your boiler's internal computer has encountered a critical communication error and cannot safely operate your heating or hot water.
F0242 High Your boiler's internal computer has encountered a critical communication error and cannot operate safely.
F0258 High Your boiler's internal computer has encountered a critical communication failure or hardware fault, meaning it cannot process commands to heat your home.
F0262 High Your boiler's main internal computer or its configuration chip has developed a fault and can no longer communicate correctly with the rest of the system.
F0272 High Your boiler's internal computer has encountered a critical communication error and cannot tell the system to start heating.
F0280 High Your boiler's internal computer has encountered a critical error or is not communicating properly, meaning the system cannot run.
F0290 High Your boiler’s internal computer has lost contact with a vital control chip, meaning the system cannot run safely and will stay locked out.
F1259 High Your boiler's main internal computer or its configuration module has developed a communication failure, preventing the system from operating safely.
F1263 High Your boiler's internal computer has developed a fault and can no longer communicate with the main control system, meaning it cannot operate safely.
F7228 High Your boiler detects a flame when there shouldn't be one, so it has shut down as a safety precaution to prevent gas from flowing incorrectly.
FA Emergency Your boiler is still detecting a flame even though it has tried to turn the gas off, which is a safety conflict that requires a professional inspection.
FA306 Emergency Your boiler is still detecting a flame even though the gas supply should have been cut off, which is a safety concern that prevents the unit from operating.
FD Low Your boiler has entered a temporary status because the reset button was held down for too long or pressed by mistake.
FD231 High Your boiler has lost power or experienced an electrical error while it was already trying to show a different fault code.

Worcester Bosch CDi Classic is discontinued — time for a new one?

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