150 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-814-41 | FELiS FL 50 HM NG GB Condensing Boiler | 2021–present |
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Your boiler has lost connection with the sensor that monitors the temperature outside, which may cause your heating to behave unpredictably.
Your boiler's temperature sensor has failed or is giving an incorrect reading, which means the system cannot safely monitor how hot the water is getting.
Your boiler has stopped working because it cannot correctly measure the temperature of the water circulating through your heating system.
Your boiler has detected a problem with the sensor that monitors the temperature of the exhaust fumes, causing the system to shut down for safety.
Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit.
Your boiler has detected a problem with the sensor that monitors the temperature of the water leaving the unit, preventing it from heating correctly.
Your boiler has stopped working because it cannot accurately measure the temperature of the water leaving the unit.
Your boiler has stopped working because it cannot correctly measure the temperature of the water returning from your radiators.
Your boiler system has detected a problem with the sensor that monitors water returning from the heating network, which may stop the heating from working efficiently.
Your boiler has detected a problem with the sensor that monitors the temperature of the water returning from your radiators.
Your boiler is having trouble measuring the temperature of your hot water, which usually means it cannot heat water for your taps correctly.
Your boiler is having trouble measuring the temperature of your hot water, which could mean your water stays cold or doesn't reach the right temperature.
Your boiler has detected a problem with the sensor that monitors the temperature of your hot water, meaning you may experience inconsistent or no hot water.
Your boiler has detected a problem with the sensor that manages the temperature of your hot water recirculation system, which may affect how quickly your hot water arrives at the taps.
Your boiler's internal room temperature sensor is reporting a communication problem, which may prevent your heating from turning on correctly.
Your boiler has lost communication with one of the temperature sensors used to monitor your home's warmth, which may prevent your heating from running correctly.
Your boiler has lost communication with one of its temperature sensors, which means it cannot accurately monitor the heat levels in your home.
Your boiler's hot water storage tank sensor is unable to read the temperature correctly, which may affect your supply of hot water.
Your boiler's hot water tank sensor has developed a fault, meaning the system cannot correctly monitor the temperature at the bottom of the cylinder.
Your boiler is having trouble reading the temperature in the middle of your hot water storage tank, which may affect how the system manages your hot water supply.
Your boiler has detected a fault with the sensor that monitors the temperature of the solar collector, meaning it cannot accurately read how hot the system is.
Your boiler has stopped working because it cannot correctly detect the water pressure, often due to a faulty sensor or a blockage.
Your boiler's communication system is confused because two internal components are trying to use the same identification address.
Your boiler has lost the digital connection between its main control board and the external controls or display, meaning it cannot receive the signals it needs to operate.
Your boiler's electronic control panels are having a communication argument because two components are trying to use the same digital identity.
Your boiler has lost its wireless connection with the thermostat or remote control unit, meaning they can no longer talk to each other to manage your heating.
Your boiler's internal memory chip is overwhelmed or malfunctioning, causing the main control board to lose track of its settings.
Your boiler's internal computer is having trouble communicating with an add-on control component, which usually means the system cannot manage your heating or hot water correctly.
Your boiler has lost communication with an internal control expansion module, meaning the system cannot correctly manage certain heating functions.
Your boiler's internal clock or timer control system has encountered a synchronization error, causing the unit to stop running.
Your boiler's internal clock has lost its power backup, meaning your timed heating schedules may be lost or reset.
Your boiler's internal computer systems have stopped talking to each other, meaning the unit cannot function or receive instructions.
Your boiler has detected that the water inside is getting too hot, causing it to shut down for safety.
Your boiler has shut down because it has detected an unsafe increase in temperature, triggered by an overheat protection switch.
Your boiler has shut itself down because it detected that the internal temperature has become dangerously high.
Your boiler has too much water inside it, which is putting excess pressure on the system.
Your boiler has stopped working because there is not enough water pressure in the system to operate safely.
Your boiler has stopped working because the water pressure is too low for the system to run safely.
Your boiler is struggling to get the water in your radiators up to the required temperature, meaning your heating may feel lukewarm or fail to warm up properly.
Your boiler's secondary heating zone is not reaching the required temperature, meaning some of your radiators or underfloor heating may stay cold.
Your boiler has shut down because the internal water temperature has become too hot.
Your boiler is struggling to get your hot water up to the right temperature, meaning your taps or shower may only be lukewarm.
Your boiler has failed to heat the stored water to a high enough temperature to kill off bacteria, usually because the hot water hasn't been used for a while or the heating cycle timed out.
Your boiler started correctly but the flame went out unexpectedly while it was running, causing the system to shut down for safety.
Your boiler is not receiving the correct amount of air to burn gas safely, causing the system to lock out for your protection.
Your boiler has shut down because it detected that the exhaust gases are getting too hot, which is a safety feature to prevent damage to the internal components.
Your boiler has stopped working because it has detected an issue with the gas pressure, causing it to shut down for safety.
Your boiler has tried to light several times but has failed to produce a flame, meaning your heating and hot water will not work.
Your boiler has become confused because its main control board and internal settings do not match, meaning it doesn't know how to operate properly.
Your boiler's internal computer has encountered a technical glitch and can no longer control the heating process safely.
Your boiler's internal computer has lost its settings or is confused by the programmed instructions, causing it to stop working for safety.
Your boiler has been manually locked, likely by someone pressing the reset button for too long or a technician during maintenance.
Your boiler's fan is not spinning fast enough to safely clear away exhaust fumes, causing the system to shut down for safety.
Your boiler has stopped working because it cannot confirm that the fan is correctly clearing exhaust gases from the system.
Your boiler has detected that the water pressure or flow within your heating system is too low to operate safely.
Your boiler has stopped working because it cannot confirm that the fan is clear of old gases before starting the ignition process.
Your boiler's electronic control system has detected a communication problem with its internal combustion safety sensors, preventing it from firing up safely.
Your boiler has lost the ability to monitor its own water pressure, meaning it cannot operate safely and has shut down.
Your boiler has detected an external alert or safety signal from an accessory like a thermostat or zone controller, which has temporarily stopped the heating.
Your boiler has detected that an external safety device or secondary system limit has been triggered, causing the unit to shut down for protection.
Your boiler has detected that an external safety device or specialized accessory connected to it has been triggered, causing the system to shut down.
Your boiler has detected an issue with an external safety device or accessory connected to its auxiliary circuit, causing it to stop running for protection.
Your boiler has detected that the water pressure inside the system has reached a level that is too high for safe operation.
Your boiler has detected that the water pressure has dropped too low to operate safely, causing the system to shut down.
Your boiler has shut down because it detected that the water in the heating system has become too hot, triggering a safety cut-out to prevent damage.
Your boiler's secondary heating zone has reached an unsafe temperature and has shut down to prevent damage.
Your boiler is currently stuck in a technical setup or configuration mode rather than its normal operating state.
Your boiler has timed out while trying to refill or reheat its internal water storage, which usually indicates a blockage or a failing internal pump.
Your boiler has stopped working because it has exceeded its pre-set limit for filling the system with water this week, which often suggests a leak.
Your boiler has detected an issue with the water circulation or temperature in your central heating system, causing it to shut down for safety.
Your boiler has stopped working because the internal pump or motor is not spinning at the correct speed to circulate water correctly.
Your boiler has detected a problem with how it moves air and gases through the system, causing it to shut down for safety.
Your boiler has detected an internal electrical communication failure between its main control boards, causing the system to shut down for safety.
Your boiler has detected a problem with one of its internal temperature sensors, which means it cannot monitor heat levels safely and has stopped working.
Your boiler has detected that the water pressure is incorrect, causing the system to shut down for safety.
Your boiler is having trouble measuring how efficiently it is running because of a problem with an internal water flow sensor.
Your boiler has detected an issue with a temperature sensor that monitors water returning to the unit, meaning it cannot accurately measure how efficiently it is running.
Your boiler has detected an issue with the sensor used to monitor the temperature of your swimming pool heating circuit.
Your boiler has detected a problem with one of the sensors that measures the temperature of the water leaving the unit, meaning it cannot safely heat your home or water.
Your boiler has detected that water is heating up too quickly or unevenly, causing it to shut down to prevent internal damage.
Your boiler has detected that the electricity supply from your home is fluctuating and is outside the safe limits required for the system to operate properly.
Your boiler is struggling to accurately measure the temperature of the water used for your taps and shower, so it has stopped heating it to prevent overheating.
Your boiler is currently unable to monitor the temperature of your hot water properly, so it has safely shut down the hot water function to prevent overheating.
Your boiler has detected that the water pressure inside the system has risen above the safe operating limit.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler's electronic control system is confused because it is receiving conflicting or identical signals from two different sensors, causing it to shut down for safety.
Your boiler's external controller or optional accessory module is sending conflicting data, causing the system to stop working as a precaution.
Your boiler's heating control system is confused because it is receiving conflicting or duplicate temperature information from its sensors.
Your boiler has detected a communication error or conflict involving an external accessory, such as an extra pump or zone controller connected to the system.
Your boiler is struggling to correctly manage the air and gas mixture needed to safely and efficiently create a flame.
Your boiler's internal control system is confused because two separate components are trying to perform the same task at the same time.
Your boiler has lost the signal from an external temperature sensor, which means it cannot correctly calculate how much heat it needs to provide.
Your boiler has lost its connection to an external sensor, preventing it from correctly monitoring your heating system's temperature.
Your boiler has lost the signal from one of its internal temperature sensors, causing it to stop operating to ensure safety.
Your boiler is struggling to read a specific temperature sensor, which is causing it to stop operating to ensure your safety.
Your boiler has lost connection to a critical internal component, meaning it cannot properly monitor its own temperature and has shut down to stay safe.
Your boiler has lost communication with an external accessory or sensor, causing it to stop operating because it cannot confirm the system's status.
Your boiler has detected an internal electrical safety failure and has shut down to prevent damage or unsafe operation.
Your boiler has lost communication with the pump responsible for moving water through your heating system, meaning it cannot safely heat your home or water.
Your boiler has lost its connection to the external pump that moves water through your heating system, meaning it cannot circulate heat to your radiators or taps.
Your boiler is struggling to communicate with a key internal temperature sensor, preventing it from safely heating your water.
Your boiler is having trouble communicating with the solar panel sensor, meaning it cannot accurately detect energy from your solar setup.
Your boiler is struggling because it cannot detect or communicate with the solar water heating system connected to your home.
Your boiler's solar energy system is unable to detect a required component, meaning the solar heating integration is currently inactive.
Your boiler is reporting a connection issue with an optional solar-powered swimming pool heating add-on that does not appear to be installed or is not communicating correctly.
Your boiler has lost its connection to the water circulation pump, meaning it cannot push heat around your home or to your taps.
Your boiler's electronic control system is failing to detect a necessary temperature sensor, meaning the unit cannot safely manage its heat output.
Your boiler's electronic control system is failing to recognize its own internal address, preventing it from starting up correctly.
Your boiler has detected that a component responsible for managing waste water flow is not communicating correctly, causing the system to stop working to prevent internal flooding.
Your boiler is having trouble communicating with its external water storage tank, preventing it from knowing how much hot water is available.
The boiler's central control computer is having a communication breakdown with the internal water pump, meaning the system cannot circulate heat around your home.
Your boiler's internal computer is unable to communicate with its pressure sensor, meaning it cannot verify if there is enough water in the system to run safely.
Your boiler has lost communication with a key temperature sensor, causing it to shut down for safety reasons to prevent overheating.
Your boiler is having trouble accurately measuring the temperature of the water flowing to a specific part of your heating system, so it has stopped that circuit to be safe.
Your boiler has detected that the water temperature in one of your heating zones has become dangerously high and has shut itself down to prevent damage.
Your boiler has lost communication with an extra system component, such as an external controller or a zone management device, preventing it from functioning correctly.
Your boiler's internal computer is experiencing an error while calculating its operating parameters, which prevents it from starting correctly.
Your boiler is struggling to control the internal air or gas flow, which prevents it from igniting or maintaining a steady flame.
Your boiler has detected that the combustion readings are outside of safe limits, meaning it cannot operate efficiently or safely.
The boiler is unable to perform an internal safety self-check, so it has stopped operating to prevent potentially unsafe combustion.
Your boiler is attempting to restart too many times after failing to ignite, and it has now locked itself out for safety.
Your boiler is struggling to ignite or maintain a flame because it is failing to start up reliably over several attempts.
Your boiler has detected an issue with its internal electrical communication or lighting system, which is preventing it from operating correctly.
Your boiler has stopped working because the electrical supply from the mains power is too low for the system to operate safely.
Your boiler has stopped working because the fan that clears out exhaust gases is rotating at the wrong speed, causing the system to shut down for safety.
Your boiler is struggling to push out waste gases because it cannot correctly measure the airflow inside the flue system.
Your boiler is struggling to detect the temperature of your hot water, so it has stopped providing it to prevent overheating.
Your boiler has lost its connection to the remote thermostat or controller you use to set your heating temperature.
Your boiler is currently unable to communicate with its remote thermostat or room control panel, preventing it from knowing when to turn the heating on.
Your boiler has lost communication with its room thermostat, meaning it cannot detect the temperature of your home to know when to heat up.
Your boiler has shut down because it has detected an unsafely high temperature at the water outlet.
Your boiler has detected that the water leaving the unit is freezing or at an impossibly low temperature, which has caused it to shut down to prevent damage.
Your boiler has shut down because the water inside has become dangerously overheated.
Your boiler has detected an impossibly cold temperature reading on its internal return pipe, which is usually caused by a frozen pipe or a faulty sensor.
Your boiler has detected that the water returning to the unit is far too hot, causing it to shut down to prevent overheating.
Your boiler is struggling to detect that the flue system is properly open, which prevents it from safely venting gases.
Your boiler is having trouble communicating with the ventilation flap that controls the flow of exhaust gases, so it has stopped working for safety reasons.
Your boiler has detected that the water pressure inside the system is dangerously high, which has triggered a safety shutdown to prevent internal damage.
Your boiler has detected that the water pressure inside the system has dropped too low to operate safely and effectively.
Your boiler has detected an issue with the sensor that measures the temperature of the internal water flow, causing it to shut down for protection.
Your boiler's external outdoor temperature sensor is either disconnected or faulty, meaning the system doesn't know how cold it is outside to adjust its heat settings.
Your boiler has detected that the water inside the heating system is getting too hot and has automatically shut down to prevent damage.
Your boiler has switched itself off because it has detected that it is getting dangerously hot, preventing it from starting up again for your safety.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent damage or dangerous overheating.
Your boiler has detected an extremely low temperature reading that is below freezing, causing the system to stop working for safety.
Your boiler has shut down because it has detected a dangerously high temperature inside the system, indicating it is overheating.
Your boiler has detected that the water temperature is freezing or the sensor is sending a false sub-zero reading, causing the system to shut down to prevent damage.
Your boiler has detected that the water returning to the unit is significantly hotter than the safe limit, causing it to shut down to prevent damage.
Your boiler has shut down because it detected that the water temperature has exceeded safe limits, indicating it is overheating.
Your boiler has shut down because it detected that the water temperature leaving the unit has become dangerously hot.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes