137 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler's internal computer parts are struggling to talk to each other, which means the system cannot receive the signals it needs to turn on.
This is a configuration setting that shows the boiler is automatically calculating the most efficient power level needed to heat your home.
Your boiler is currently performing a routine cooling down process where the internal pump continues to run after the heating has switched off.
Your boiler is taking a planned break to prevent the system from turning on and off too frequently, which helps save energy and protect internal parts.
Your boiler is currently displaying the live temperature of the water inside your hot water storage cylinder.
Your boiler is simply displaying the target temperature it is currently trying to reach for your heating, which is a normal status message rather than an actual fault.
Your boiler is displaying the target temperature for your hot water, which is a normal status reading rather than a breakdown.
Your boiler is currently displaying the target temperature setting for your hot water storage tank rather than a fault.
This is a normal status code showing whether your external heating controls are currently asking the boiler to provide heat or not.
Your boiler is simply displaying the target temperature being requested by your external thermostat, rather than indicating a breakdown or internal fault.
Your boiler is simply showing whether its internal water pump is currently running or resting.
Your boiler is simply indicating whether its internal pump is currently running or resting while distributing heat through the system.
Your boiler is simply showing whether the water pump for your hot water is currently running or not; this is a status update rather than a fault.
Your boiler is currently set to a specific speed for its internal pump rather than adjusting it automatically based on your home's needs.
Your boiler is simply displaying the current operating speed of its internal pump as a percentage, which is a normal status message rather than an error.
This is a status indicator rather than a fault, showing whether your external heating controls are currently asking the boiler to turn on or stay off.
Your boiler has been adjusted to measure the temperature of the water returning from your radiators rather than leaving the boiler, which is a standard setting often used for underfloor heating systems.
Your boiler is simply showing its current pump setting and is not experiencing a fault; it is just letting you know whether the pump is running constantly or intermittently.
Your boiler is displaying a status message about how your internal pump is currently configured to run, rather than a dangerous fault.
Your boiler is currently set to its maximum limit for how hot your water is allowed to get.
This is a status indicator showing whether the pre-heat function for your hot water is currently switched on or off, rather than an actual fault code.
This is actually a status indicator rather than a fault, showing whether your boiler 'thinks' your hot water tank is currently asking for heat.
Your boiler is currently set to summer mode, which means it will only provide hot water and will not turn the radiators on.
Your boiler is checking whether there is enough water pressure to run safely, but it hasn't yet confirmed if the pressure switch is active.
This is a status indicator showing whether your boiler is currently set to pre-heat your hot water tank or maintain a warm start for your taps.
Your boiler is confused about how it should be controlling an external part, such as a pump or valve, because the settings for its internal switch are incorrectly configured.
Your boiler is notifying you of how an internal control module is currently configured to handle external components like pumps or valves.
Your boiler is displaying a setting information code rather than a fault, indicating how the system manages its own water pressure levels.
Your boiler is displaying the real-time speed of the internal fan as part of its normal diagnostic checks, which is usually just an information code rather than a breakdown.
Your boiler is currently showing its internal fan speed information rather than a fault, which usually indicates the system is performing a diagnostic check or starting up.
Your boiler is simply showing you whether it is currently sending heat to your radiators, your hot water tank, or both at the same time.
Your boiler is simply displaying the current speed of your hot water flow as an informational check rather than reporting a breakdown.
Your boiler is simply displaying the current temperature of the water in your solar heating panels.
This is not actually a fault code, but an information screen showing the current temperature of the water heading to your radiators.
This is an information code rather than a fault, showing you the temperature of the water as it returns to the boiler from your radiators.
Your boiler is currently set to a low-temperature efficiency mode which may prevent your radiators from getting as hot as you expect during very cold weather.
Your boiler is notifying you of a specific setting adjustment related to how it calculates the temperature needed for your radiators based on the weather.
Your boiler is displaying the current reading from its outdoor weather sensor to adjust how it heats your home.
Your boiler is adjusting the lowest speed of the internal fan to ensure it runs efficiently at low power levels.
Your boiler is automatically adjusting its fan speed to compensate for issues with the air supply or flue gases.
This is a configuration setting for your solar water heating system that controls whether your boiler automatically heats your water to a high temperature to kill bacteria.
Your boiler is recording how many times it has been forced to shut down because it grew dangerously hot, which usually points to a circulation or sensor issue.
Your boiler is struggling to light correctly and has recorded multiple failed attempts to start up.
Your boiler is currently operating in a lower-power mode to save energy during the night or a scheduled period of reduced activity.
Your boiler is displaying an information message showing how long it typically takes for the burner to light, rather than a technical fault.
Your boiler is displaying a status code showing how long the burner is taking to fire up, which usually indicates the system is working harder than normal to ignite.
This is a settings status message indicating whether your boiler's pre-heat feature for hot water is currently switched on or off.
Your boiler is currently taking a temporary rest to prevent it from turning on and off too frequently, which helps protect the internal components.
Your boiler is struggling to fire up on the first try and is recording how many times it has failed to ignite.
Your boiler is struggling to light itself and has failed several attempts to start up.
Your boiler is currently set to a specific service mode that forces the internal valve into a fixed position rather than operating normally.
Your boiler has stopped working because it cannot communicate with the sensor that monitors the temperature of the water leaving the unit.
Your boiler has stopped working because it can no longer monitor the temperature of the water coming back from your radiators.
Your boiler has detected an electrical fault with the sensor that monitors water temperature, causing it to stop heating for safety.
Your boiler has detected an electrical fault with the sensor that monitors water returning from your radiators, causing the system to stop working for safety.
Your boiler has lost communication with the hot water cylinder temperature sensor because of an electrical fault, meaning it cannot safely tell if your water is hot enough.
Your boiler has shut itself down because it has become too hot to operate safely.
Your boiler has stopped working because there is not enough water pressure in the system to operate safely.
Your boiler has shut down because the internal water temperature is rising too quickly or unevenly, usually due to a circulation blockage.
Your boiler is overheating too quickly because water isn't moving through the system properly, causing it to shut down for safety.
Your boiler has shut down because the exhaust gases have become too hot, which is a safety mechanism to prevent internal damage.
Your boiler has detected a flame when there shouldn't be one, so it has shut down as a safety precaution.
Your boiler has tried to light several times but has been unable to establish a flame, meaning you have no heating or hot water.
Your boiler has lost its flame while it was running and cannot manage to light itself back up.
Your boiler has detected a problem with the fan that safely removes exhaust gases, meaning it has shut down as a safety precaution.
Your boiler has identified a problem with how it moves air and fumes through the system, preventing it from starting safely.
Your boiler's internal communication system has lost power or experienced a short circuit, preventing the controls from talking to the main unit.
Your boiler has detected a communication error with the gas valve, preventing it from safely lighting the burner for heating and hot water.
Your boiler has detected that the gas valve is not closing as quickly as it should, which is preventing the unit from operating safely for your protection.
Your boiler's internal computer brain is struggling to process its saved memory, which has caused the system to stop working for safety.
Your boiler has detected an internal electrical communication error or a faulty sensor that is preventing it from running safely.
Your boiler's internal control board has become too hot and has shut itself down to prevent any damage to the electronics.
Your boiler’s control board is receiving an incorrect electrical signal from the flame sensor, meaning it cannot safely confirm if the burner is lit.
Your boiler is struggling to keep a steady flame lit, which is causing the system to shut down for safety.
Your boiler’s control board has forgotten which model it is supposed to be, usually after a part has been replaced or due to a memory error.
Your boiler has detected that one of its internal thermometers has stopped responding or is stuck on a single temperature reading, preventing it from heating safely.
Your boiler has detected that the sensors measuring water temperature are giving conflicting readings or have failed, preventing the system from heating safely.
Your boiler is unable to accurately measure the water pressure because the internal sensor is sending an incorrect or missing signal.
Your boiler has detected that the water pressure is too high, or the internal sensor that monitors pressure has developed a fault.
Your boiler is unable to sense a change in water pressure when the pump starts up, preventing it from firing for safety.
Your boiler has shut down because a safety sensor has detected that the main heating component is dangerously overheating.
Your boiler is having trouble clearing away excess water or exhaust gases, causing it to shut down for safety.
Your boiler is having trouble communicating with the hot water sensor in your external control box, meaning your hot water may not reach the desired temperature.
Your boiler has detected that its temperature sensors aren't registering a change in heat when the burner is on, which is often caused by a lack of water or a sensing error.
Your boiler is confused because its internal thermometers are giving conflicting readings, causing it to shut down to prevent overheating.
Your boiler has detected that a temperature sensor is either loose or has been fitted to the wrong pipe, preventing it from reading the heat levels correctly.
Your boiler has detected an issue with the electrical connection to your underfloor heating system, preventing that part of your home from warming up properly.
Your boiler is struggling to spark correctly to light the gas, meaning it cannot provide heating or hot water until the ignition system is fixed.
Your boiler has detected a problem with how it controls the gas supply, meaning it cannot safely light the flame to provide heating or hot water.
Your boiler has stopped working because the internal pump that moves water around your heating system has failed or is struggling to turn.
Your boiler has stopped working because the water pressure is too low for it to operate safely.
Your boiler is currently running an automatic maintenance program to remove trapped air bubbles from the heating pipes.
Your boiler is performing a routine self-cleaning process to remove air bubbles from the pipes and is not currently experiencing a fault.
Your boiler is working perfectly well but is currently resting because your thermostat or timer is not telling it to turn the heating on.
Your boiler is currently preparing to start the heating cycle by running its internal fan to clear out any residual gases.
Your boiler is simply completing a short preparation cycle to move water around the system before the burner ignites.
Your boiler is currently in the process of lighting its burner to start heating your home; this is a normal status message and not a fault.
Your boiler is working perfectly and is currently running specifically to provide heating for your radiators.
Your boiler is simply taking a short break to circulate water and cool down internal parts after a period of heating.
Your boiler is simply running its internal fan for a few minutes to clear out heat or gases after a heating cycle and will resume normal operation shortly.
Your boiler is briefly running its internal pump after a heating cycle to safely move remaining heat away from the unit.
Your boiler is currently taking a short, planned break to allow heat to dissipate after finishing a heating cycle.
Your boiler is currently working correctly and is simply indicating that it has received a signal to start heating up your hot water cylinder.
Your boiler is currently preparing itself for a hot water demand by clearing the internal combustion chamber with the fan.
Your boiler is currently firing up its burner to heat your hot water tank.
Your boiler is working perfectly and is currently heating up the water for your taps or cylinder.
Your boiler is simply cooling itself down for a few minutes after heating your water, which is a normal part of its operation.
Your boiler is briefly cooling down its internal components after finishing a cycle of heating your hot water.
Your boiler is briefly running its pump after heating your water to safely clear away excess heat, which is a normal part of its operation.
Your boiler is working normally and is simply indicating that it has received a request to heat your hot water cylinder.
Your boiler is performing a routine start-up check by running its internal fan before beginning to heat your water.
Your boiler is simply preparing to heat your hot water and is performing a quick internal check before it starts.
Your boiler is simply letting you know it is currently in the process of lighting the burner to provide hot water for your taps or tank.
Your boiler is not broken; it is simply letting you know that it is currently firing the burner to heat your hot water.
Your boiler is briefly keeping the pump running to cool down internal components after providing hot water.
Your boiler is briefly keeping the internal fan running after a hot water cycle to clear out leftover heat and exhaust gases.
Your boiler is briefly keeping the pump running after heating your hot water to safely dissipate excess heat from the internal system.
Your boiler has temporarily paused the burner because the water reaching the hot water tank is already hot enough and the system is waiting for the temperature to drop slightly before restarting.
Your boiler is working fine, but your wall thermostat or heating controls have told it to stay switched off.
Your boiler is not broken; it is simply in 'Summer Mode' because the heating is switched off or your thermostat is set lower than the current room temperature.
Your boiler's fan is not spinning at the correct speed, which is preventing the system from safely starting the ignition process.
Your boiler is waiting for the air pressure sensor to confirm the fan is working correctly before it continues the ignition process.
Your boiler has sensed that the temperature inside is too low and has automatically turned itself on to prevent the water from freezing and damaging the pipes.
Your boiler has paused because it has detected that an external safety switch for your underfloor heating has been triggered or disconnected.
Your boiler has detected that there is too much water in the system, which puts unnecessary stress on the internal seals and components.
Your boiler is unable to start because a safety valve designed to stop exhaust fumes from flowing back into the unit is stuck in the closed position.
Your boiler is temporarily running at its lowest power setting to prevent it from overheating while it waits for the system temperature to drop.
Your boiler has temporarily paused operation because it has detected an issue with the water flow, likely caused by low pressure or a blockage in the system.
Your boiler has temporarily stopped working because there is not enough water pressure or flow to safely heat your home.
Your boiler is currently running an automatic program to clear trapped air from the system, which often happens after a restart or maintenance.
Your boiler is currently set to a 'showroom' demonstration mode, which allows the display to work but prevents the unit from actually heating your water or radiators.
Your boiler is temporarily paused because it is double-checking that its internal temperature sensors are reading correctly before it continues to heat your home.
Your boiler has paused itself to run a safety check on its internal water pressure sensor, meaning your heating and hot water are temporarily unavailable.
Your boiler is temporarily paused because it is checking its internal temperature sensors to ensure the system is working correctly.
Your boiler has noticed the water pressure is low and is automatically refilling itself to the correct level.
Your boiler is briefly clearing out the air inside to ensure a safe burn before it starts the heating process.
Your boiler is currently taking a break because it has finished heating your home and is waiting for the next request for warmth.
BoilerFaultCodes