128 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 has safely shut down to prevent incorrect operation.
Your boiler has detected multiple internal communication issues, meaning it cannot correctly coordinate its parts to provide heating or hot water.
Your boiler's internal electronic control system for the heat pump unit is failing to communicate properly, causing the system to stop operating.
Your boiler is having trouble communicating with your wall-mounted thermostat, which is preventing it from knowing when to turn the heating on.
Your heat pump's outdoor brain is experiencing a software or hardware communication failure, which means your heating and hot water will no longer work.
Your boiler's electronic control system for the pump is experiencing a communication fault, preventing the unit from circulating heat properly.
Your boiler is having trouble detecting the temperature of a key internal cooling component, which means it cannot operate safely and has shut down to protect itself.
Your boiler is struggling to accurately measure the temperature of the water leaving it, so it has safely shut down to prevent overheating.
Your boiler's temperature-sensing system is detecting an inaccurate reading, causing it to shut down to prevent potential overheating.
Your heat pump is unable to read the temperature inside its cooling system, preventing it from safely heating your home.
Your boiler has detected a communication problem with one of its internal temperature sensors, causing it to stop operating as a safety precaution.
Your boiler is struggling to detect the temperature outside, which may cause it to run less efficiently or prevent it from heating your home correctly.
Your boiler has detected a faulty internal temperature sensor, meaning the system cannot safely monitor its own heat levels and has shut down as a precaution.
Your boiler's internal computer system is confused because two or more communication components are trying to send data at the exact same time.
Your boiler has detected that the internal water pressure is too high, causing it to shut down for safety to prevent damage.
Your boiler is struggling to accurately measure how much water pressure is inside the system, which is preventing it from safely starting your heating or hot water.
Your heat pump is detecting an electrical issue with its internal motor, causing it to shut down to prevent further damage.
Your heat pump is struggling to start its internal motor, causing the system to stop running to prevent electrical damage.
The external unit that helps power your heating system is currently unable to run its cooling fan, which prevents the system from operating correctly.
Your heat pump is unable to move water around the system correctly, which means your heating and hot water will stop working until the connection or pump is repaired.
Your boiler has lost the connection to the thermometer placed outside your home, so it cannot automatically adjust your heating based on the outside temperature.
Your boiler is receiving incorrect temperature readings from a sensor used when multiple units are linked together, causing it to stop operating correctly.
Your boiler has lost the connection to the temperature sensor located outside your home, so it cannot accurately judge how hard it needs to work based on the weather.
Your heating system has detected an electrical problem with the sensor that measures the temperature of the water flowing into your home, meaning it cannot safely control the heating or hot water until this is resolved.
Your boiler is struggling to accurately measure the temperature of the water returning to it, so it has shut down to prevent potential overheating.
Your boiler is struggling to detect the temperature of your hot water supply, so it has safely shut down the hot water system to prevent overheating.
Your boiler has lost its connection to the wall-mounted temperature sensor in your home, meaning it doesn't know when to turn the heating on or off.
Your boiler is having trouble communicating with your secondary room thermostat or heating control unit.
Your boiler has lost the ability to communicate with another connected heating unit or the system's control network, meaning the boiler has stopped working to prevent potential configuration errors.
Your boiler's internal communication system is confused because multiple connected components have been assigned the same identification number.
Your boiler is experiencing a communication fault between its internal control systems, which prevents it from operating safely.
Your boiler's internal communication system is confused because two or more internal parts are trying to use the same digital 'address' at the same time.
Your boiler's internal control system is confused because it is receiving conflicting timing information from two different parts of the unit.
Your boiler's internal clock has lost its memory settings, which may cause your heating schedule to reset or fail to trigger when expected.
Your heat pump is struggling to gather enough heat from the outside air, likely due to extremely cold weather conditions or a blockage in the unit's airflow.
Your boiler is having trouble communicating with the setting that controls your hot water temperature, which may result in no hot water being produced.
Your boiler has failed to reach the high temperature required to kill potential bacteria in your hot water cylinder.
Your heat pump is experiencing a recurring internal operating error that has caused it to stop working correctly to protect itself.
Your boiler's computer system has detected an internal identity error, meaning it is currently confused about how it should be configured to run your home's heating and hot water.
Your boiler has detected an external safety signal or accessory fault, which is causing it to shut down for protection.
Your boiler is struggling to detect the temperature of the room correctly, which means it cannot decide when to turn your heating on or off effectively.
Your boiler is struggling to communicate with an external accessory, such as your heating controller or room thermostat, causing it to pause operations.
Your boiler is struggling because the electricity supply from your home to the unit is dropping below the level required to keep it running safely.
Your boiler is failing to communicate with the primary control system needed to manage your heating network.
Your boiler has lost communication with the outdoor temperature sensor, meaning it cannot automatically adjust your heating based on the weather outside.
Your boiler's secondary system is failing to heat up as expected, so your home may have limited or no heating and hot water until it is repaired.
Your heat pump is turning on and off too frequently, which has triggered a protective lockout to prevent damage to the system.
Your boiler is currently only able to provide hot water to your taps, but it is failing to send heat to your radiators.
Your boiler is correctly heating your home, but it has stopped producing hot water because it is failing to detect or activate the system that directs heat to your taps.
Your indoor unit's screen is completely blank and the system is not responding, meaning your heating and hot water are currently unavailable.
Your boiler is struggling to read the outdoor temperature, so it is defaulting to a standard operating mode until the external sensor is fixed.
Your boiler is experiencing a communication problem where the internal parts are failing to send signals to each other properly, resulting in a system shutdown.
Your boiler is having trouble measuring the temperature of the water flowing into your heating system because a temperature sensor is sending a faulty signal.
Your heat pump’s main control brain is unable to correctly communicate with the outdoor unit, preventing the system from operating properly.
Your boiler has lost the ability to accurately measure the temperature of the water flowing through your heating system, so it has shut down as a precaution.
Your boiler is struggling to accurately measure the temperature of the water returning to it, so it has stopped working to prevent potential damage.
Your boiler is struggling to accurately read the temperature of your hot water, which means it will likely stop producing hot water until the faulty sensor is replaced.
Your boiler has lost its connection to the wireless thermostat that tells it when to turn the heating on or off.
Your boiler's indoor unit is struggling to talk to the heat pump unit outside, causing the system to stop heating your home as a precaution.
Your boiler's heating control system is experiencing a communication error, meaning it has safely shut down until it can reliably restart.
Your boiler has lost its connection with the thermostat that controls your home's temperature, meaning it no longer knows when to turn your heating on or off.
Your boiler is struggling to accurately measure how hot the water is as it leaves the system, so it has stopped working for safety reasons.
Your heat pump is unable to read the temperature of its internal cooling system, preventing it from operating safely.
Your boiler has detected a faulty reading from an internal temperature sensor, meaning it has temporarily shut down to prevent potential overheating.
Your boiler is struggling to read the outdoor temperature, so it is using a default setting to ensure your heating still works.
Your boiler is struggling to communicate with its internal control system, which means it will stop working until the connection is restored.
Your boiler's internal communication system is confused because two parts are trying to use the same identification address, preventing the system from operating correctly.
Your boiler's internal communication system is experiencing an electrical connection issue, preventing it from operating correctly.
Your boiler has detected an internal electrical safety trip, which has caused it to shut down to prevent potential damage or danger.
Your heat pump is unable to communicate properly with its motor, causing the system to stop operating to prevent damage.
Your heat pump's outdoor fan is not spinning correctly, which is preventing the system from heating your home properly.
Your boiler's internal communication system is confused because it is receiving conflicting timing signals from two different parts of its electronic control system.
Your boiler has lost its internal time settings, which might prevent your heating schedules from working correctly.
Your boiler is simply reminding you that its annual scheduled maintenance is now due to ensure it remains safe and efficient.
Your heat pump is unable to draw enough warmth from the outside air, which is preventing it from heating your home efficiently.
Your boiler is having trouble communicating the correct temperature settings for your hot water, which may cause your hot water supply to behave inconsistently or stop heating up.
Your boiler has failed to reach the high temperature required to kill bacteria in your hot water system.
Your heat pump is reporting a persistent technical issue that prevents it from operating correctly to provide your heating and hot water.
Your boiler's internal computer is struggling to recognise its own settings, meaning it cannot safely start up until the configuration is reset.
Your boiler has detected an external alert from an add-on device, such as a high-limit thermostat or fire safety switch, which is telling the system to shut down for safety.
Your boiler has lost connection to the temperature sensor that monitors your room environment, so it cannot accurately tell if your home needs more heat.
Your boiler has detected an issue outside of its main internal components, often related to an external accessory like a smart thermostat, external sensor, or communication fault between connected devices.
Your heat pump unit is struggling to communicate with the system, meaning your heating or hot water may stop working until the connection is restored.
Your boiler has detected that the electricity supply coming from your wall socket or fused spur is too weak or unstable to operate safely.
Your boiler is struggling to communicate with the main controller that manages the heating system, preventing it from starting up correctly.
Your boiler is struggling to communicate with the temperature sensor located outside your home, which helps it decide how hard to work based on the weather.
Your boiler has lost communication with the weather sensor installed outside your home, meaning it can no longer automatically adjust its settings based on the outside temperature.
Your boiler has stopped heating the water because it cannot detect a rise in temperature, which means you currently have no heating or hot water.
Your boiler has lost communication with the temperature sensor located outside your home, so it cannot automatically adjust your heating based on the weather.
Your boiler has detected an external signal error, likely from an add-on device or a communication fault between the boiler and its smart control system.
Your boiler has received a signal from your energy provider indicating that low-tariff electricity is currently active, and it is adjusting its operation to save you money.
Your boiler has been temporarily disabled by an external control signal, often because an energy management system or a smart sensor has triggered a safety lock.
Your boiler has detected that the water leaving the system is getting too hot, so it has safely shut itself down to prevent damage.
Your heat pump is reporting that an internal component is running too hot, causing the system to automatically shut down to prevent damage.
Your boiler has detected that there is not enough water circulating through the system, meaning it cannot safely produce heat or hot water.
Your boiler has been temporarily disabled because it is receiving a signal to shut down from an external energy management or smart device.
Your boiler has lost communication with the outdoor sensor that monitors outside temperatures, meaning it cannot automatically adjust your heating performance based on the weather.
Your boiler has lost communication with the outdoor sensor that monitors outside temperatures, meaning it cannot automatically adjust your heating performance.
Your boiler is struggling to read the temperature outside, which is preventing it from heating your home properly.
Your heat pump is experiencing a technical issue with the electronic system that controls the output of the unit, meaning your heating and hot water may not work correctly.
Your boiler is struggling to communicate correctly with the outdoor unit, likely due to a temporary power glitch or a disruption in the wiring signal.
Your heat pump is struggling to read the outdoor temperature, which prevents it from operating correctly.
Your boiler has detected an issue with a heat sensor that monitors its internal cooling system, preventing it from operating correctly.
Your heat pump is struggling to read the temperature outside, which means it cannot correctly adjust its performance to keep your home warm.
Your boiler's external temperature sensor is detecting an issue, so the system has paused to prevent a potential fault.
Your heat pump is struggling to read the outdoor temperature correctly, which prevents it from properly managing ice buildup on the unit.
Your boiler's external sensor is struggling to communicate, which means the system cannot accurately measure the outdoor temperature to adjust your heating effectively.
Your heat pump is struggling to read the outdoor temperature, which prevents it from calculating how to heat your home efficiently.
Your heat pump is struggling to read external temperature data, which prevents the system from regulating its internal cooling cycle correctly.
Your boiler is struggling to communicate with the outdoor weather sensor or the heat pump unit, causing it to pause normal operation.
Your boiler is struggling to read the outdoor temperature, which means it cannot automatically adjust itself to provide the most efficient heating for the current weather.
Your heat pump has automatically shut down because it detected an electrical surge or power issue that could damage the system's internal motor.
Your heat pump is unable to start the part responsible for moving heat into your home, meaning your heating and hot water will not work until this is resolved.
Your heat pump is struggling because the outdoor fan is not spinning properly, which means the system cannot effectively produce heating or hot water for your home.
Your heat pump is struggling to read the temperature of the air it is trying to heat or cool outside your home.
Your heat pump is reporting that its internal cooling system is getting too hot, so it has safely shut down to prevent damage.
Your heat pump is detecting that the pressure in the system is currently too low for it to operate correctly.
Your heat pump is having trouble communicating with or receiving power from its outdoor unit, which means your system cannot generate heating or hot water until this connection is restored.
Your boiler has lost communication with the outdoor sensor that helps it adjust your heating based on the outside temperature.
Your boiler has detected that the water inside the heating system is not flowing correctly, causing the internal temperature to rise dangerously high.
Your boiler has detected that water is not moving correctly around your heating system, which means it cannot provide heat or hot water to your home.
Your heat pump is struggling to read the temperature of the air leaving its cooling system, which might stop the unit from heating or cooling your home properly.
Your boiler is having trouble communicating with the external air source unit, which means it cannot properly manage heating and hot water production.
Your boiler has detected that water is not circulating correctly through the system, so it has safely shut down to prevent internal damage.
Your heat pump is struggling to move water between the outside unit and the rest of your home, which means your heating and hot water will likely be unavailable.
Your heat pump is sensing that the water leaving the unit is reaching an dangerously high temperature, so it has stopped running to prevent damage.
Your heat pump is reporting that its internal cooling system has become too hot, causing the unit to stop working to protect itself from damage.
Your boiler has detected that the water pressure inside your heating system is too low to operate safely and effectively.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes