39 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Promax SL
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
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Your boiler has stopped working because it cannot properly move the gases required for combustion to safely leave the system.
Your boiler is failing to start because it isn't receiving enough electricity from your home's power supply.
Your boiler has switched itself off because it has detected that its internal temperature has become dangerously high.
Your boiler's electronic control centre is experiencing a critical internal failure and can no longer safely operate the heating or hot water system.
Your boiler's internal computer has developed a fault and is failing to control the system, meaning the boiler cannot operate safely or reliably.
Your boiler has detected that there is not enough water inside the system to operate safely and has shut down to prevent damage.
Your boiler has stopped working because a sensor that measures water temperature is providing an incorrect reading or has failed, causing the system to shut down for safety.
Your boiler has detected that the electricity supply wires are connected the wrong way around, which prevents it from operating safely.
Your boiler’s internal computer has developed a fault and is failing to send the correct signals to start or maintain your heating and hot water.
Your boiler has detected an electrical connection issue with the gas control system, preventing it from lighting safely.
Your boiler has lost communication with the sensor that monitors the temperature outside your home, which may affect how efficiently it heats your radiators.
Your boiler has lost its connection to the gas valve, meaning it cannot safely ignite to provide heating or hot water.
Your boiler has lost its ability to measure the temperature of the water used for your radiators, causing the system to stop working for safety.
Your boiler has detected a problem with the sensor that monitors the temperature of the exhaust gases, causing it to shut down for safety.
Your boiler has detected a problem with the sensor that monitors the temperature of the water coming back from your radiators, preventing it from heating correctly.
Your boiler is having trouble measuring the temperature of your hot water, which usually means it won't provide hot water to your taps.
Your boiler is struggling to breathe because something is blocking the passage of air or exhaust gases through the flue pipe.
Your boiler's internal computer has detected that its gas and air settings need recalibrating to ensure it burns fuel efficiently and safely.
Your boiler's internal sensor is struggling to accurately read the water pressure, which prevents the system from operating safely.
Your boiler has detected an issue while trying to automatically adjust its internal settings for a clean and efficient flame.
Your boiler is struggling to move water around the system properly, which is causing it to overheat and shut down for safety.
Your boiler has become too hot and has shut itself down for safety, likely because the water isn't moving through the system correctly.
Your boiler has shut down because there is too much water pressure in the system, which could lead to leaks if not addressed.
Your boiler has stopped working because the water pressure in the central heating system has dropped too low.
Your boiler has detected that hot water is not moving around the system properly, causing it to shut down to prevent overheating.
Your boiler was working but the flame has unexpectedly gone out, causing the system to stop for safety reasons.
Your boiler has failed to keep its flame lit while trying to automatically adjust its settings for efficient burning.
Your boiler has switched itself off because it has detected that the exhaust gases are becoming too hot, which is a safety feature to prevent damage.
Your boiler has failed to light, which means it cannot provide the gas flame needed to heat your water and radiators.
Your boiler's internal computer has encountered a software glitch or a communication failure that is preventing it from starting up safely.
Your boiler has detected that water is not circulating correctly through the main heat exchanger, often caused by a blockage or a pump issue.
Your boiler has stopped working because the fan that clears out exhaust gases isn't spinning at the correct speed.
Your boiler has detected that there is no water moving through the system while it is trying to heat up, causing it to shut down to prevent overheating.
Your boiler has detected an issue with the electrical frequency of your home's power supply, meaning the electricity isn't entering the unit at the correct rate for it to operate.
Your boiler's temperature sensor for hot water has stopped communicating correctly, which means you may have inconsistent or no hot water at your taps.
Your boiler thinks a flame is burning even though the gas should be turned off, which causes it to shut down for safety.
Your boiler has stopped working because it isn't receiving enough electrical power from the mains supply or has suffered a sudden power drop.
Your boiler has failed to light the flame and has turned itself off for safety reasons.
Your boiler has lost its electrical connection to a key internal component and has automatically shut down to prevent damage.
BoilerFaultCodes