39 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Greenstar 4000
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Your boiler’s internal computer chip is unrecognized or has been installed incorrectly, causing the system to stop working for safety reasons.
Your boiler's internal computer memory chip is having trouble communicating, which has caused the system to shut down for safety.
Your boiler's temperature sensor for hot water has stopped working properly, meaning your taps may only provide cold or lukewarm water.
Your boiler has lost its connection to your thermostat or remote heating controller, meaning it cannot receive instructions to turn the heating on.
Your boiler's internal pump is either jammed or struggling to move water because there is too much trapped air in the system.
Your boiler's internal computer chip is missing or has lost its connection, meaning the unit cannot identify itself and has stopped working for safety.
Your boiler's internal computer has encountered a critical communication error and cannot operate safely.
Your boiler’s internal fan is not spinning fast enough to safely clear away exhaust fumes, which has caused the system to shut down for safety.
Your boiler has switched itself off because it detected that the internal fan stopped moving the air needed for safe combustion around while it was running.
Your boiler has detected that the fan was running or air was moving when it shouldn't have been, causing the system to lock out for safety.
Your boiler's fan is spinning faster than it should, which means the system has stopped running to prevent internal damage.
Your boiler has stopped working because the internal fan, which safely exhausts fumes, is not spinning or starting up.
Your boiler has detected a fault with the sensor that monitors the temperature of the water returning to the unit, causing it to stop the heating system for safety.
Your boiler is overheating because water is not moving through the system quickly enough to carry heat away.
Your boiler has detected a faulty internal temperature sensor, which means it cannot accurately monitor the water temperature and has shut down as a safety precaution.
Your boiler has shut down because it has detected that the water inside is Getting too hot, which is a safety feature to prevent damage.
Your boiler has detected an electrical fault with the internal sensor that monitors water temperature, causing the system to shut down for safety.
Your boiler has shut down because the internal water temperature has become too hot, likely due to a lack of water flow or a circulation problem.
Your boiler has sensed that it is getting too hot and has shut down as a safety precaution to prevent damage.
Your boiler has shut down because a safety sensor detected that the internal exhaust gases have reached a dangerously high temperature.
Your boiler is failing to light the gas or stay lit, which has caused it to shut down for safety.
Your boiler is failing to light the gas burner or is losing the flame while it is running, meaning you will have no heating or hot water.
Your boiler is overheating because water isn't moving through the system quickly enough, forcing it to run at its lowest power to prevent damage.
Your boiler's internal computer has encountered a critical electronic software or hardware error that is preventing it from running safely.
Your boiler thinks it can see a flame inside the system even though it should be turned off, which is a safety conflict that prevents it from starting up.
Your boiler's computer has experienced a system failure and has entered a safety mode to prevent damage.
Your boiler thinks it sees a flame when there shouldn't be one, causing it to shut down for safety purposes.
Your boiler is still detecting a flame even though it has tried to shut off the gas, which is a safety conflict causing the system to lock out.
Your boiler thinks it can still see a fire inside even though it has commanded the burner to turn off.
Your boiler has detected a potential internal gas leak during its safety checks and has shut down to keep your home safe.
Your boiler has detected a potential internal gas leak during its safety checks and has shut down to keep your home safe.
Your boiler has stopped because the reset button was held down for too long or pressed accidentally while the unit was running normally.
Your boiler has lost its connection to the main electrical supply or has detected a significant power interruption.
Your boiler is shutting down because it is heating up much faster than it should, usually due to water not flowing through the system properly.
Your boiler is currently running a self-diagnostic check to ensure the ignition system is sparking correctly before it starts up.
Your boiler is failing a self-test of its internal fan, which is preventing the system from starting up safely.
Your boiler is performing a routine check of its internal pump and may temporarily pause normal operation while it completes the test.
Your boiler is struggling to switch between providing heating and hot water because of an internal valve check failure.
Your boiler has detected an internal safety electronic error and has stopped working to prevent a malfunction.
BoilerFaultCodes