129 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Potterton Promax HE
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 reached its set temperature and is temporarily resting; everything is working exactly as it should.
Your boiler has likely detected it is getting too hot or a temperature sensor has stopped working correctly, causing it to shut down for safety.
Your boiler has become too hot and has switched itself off as a safety precaution to prevent damage.
Your boiler has temporarily lost its flame and is attempting to restart itself automatically.
Your boiler is failing to light its burner and has locked itself out for safety after several unsuccessful attempts.
Your boiler has experienced a brief digital communication glitch and is currently trying to fix itself automatically.
Your boiler has detected that the internal fan is not spinning correctly, which means it cannot safely blow away exhaust gases to start the heating process.
Your boiler is experiencing a temporary computer glitch and is trying to correct itself automatically.
Your boiler's internal memory chip has developed a communication fault or failed, meaning the unit cannot store its settings and won't fire up.
Your boiler has encountered a minor glitch and is currently pausing itself to try and fix the problem automatically.
Your boiler has encountered a general electronic or communication error and has stopped working for safety.
Your boiler has stopped working because the internal fan, which safely exhausts gases, is not spinning correctly or communicating with the control board.
Your boiler is not receiving enough electrical power from your home's supply to operate safely.
Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
Your boiler's internal computer has developed a fault and can no longer control the heating system safely.
Your boiler's internal computer brain has developed a terminal fault and can no longer control the heating process safely.
Your boiler is overheating because the water isn't moving through the system properly or there isn't enough water inside the unit.
Your boiler has detected a sensor issue that prevents it from accurately measuring temperature, meaning it cannot safely heat your home or water.
Your boiler has detected an electrical wiring issue, meaning the power supply lines are likely connected in the wrong order.
Your boiler's internal computer has developed a fault and can no longer control the heating process safely.
Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
Your boiler has too much water inside its system, which is causing it to shut down for safety.
Your boiler has stopped working because the water level inside the system has dropped too low to operate safely.
Your boiler has stopped working because there is not enough water pressure in the central heating system to operate safely.
Your boiler is not moving water through the system correctly, which is causing it to shut down to prevent overheating.
Your boiler has failed to heat the water in your cylinder to a high enough temperature to kill off any potentially harmful bacteria.
Your boiler started to heat up but the flame went out unexpectedly while it was running.
Your boiler is failing to light the gas or cannot stay lit, meaning it will not provide heating or hot water until the issue is resolved.
Your boiler has likely experienced a component failure or an internal electrical glitch and is requiring a manual reset to restart its operation.
Your boiler has detected that its built-in fan is not spinning at the right speed or has stopped entirely, preventing it from safely clearing away exhaust fumes.
Your boiler is having trouble breathing correctly and cannot safely move air or waste gases through the system.
Your boiler has detected an issue with how the water is moving through the system or a faulty sensor monitoring that flow, causing it to stop for safety.
Your boiler has stopped working because it cannot confirm that the fan is safely clearing waste gases from the system.
Your boiler has detected that it is heating up very quickly without enough water flowing through it, meaning it is at risk of overheating.
Your boiler has lost its electrical safety connection, which is preventing the system from starting for safety reasons.
Your boiler has shut down because the internal water has reached an unsafe temperature and is starting to overheat.
Your boiler has stopped working because it cannot correctly read the temperature of the water coming back from your radiators.
Your boiler has detected a problem with the sensor that monitors water temperature returning to the unit, meaning it cannot safely regulate heat.
Your boiler is confused because the water returning to it seems hotter than the water it just sent out, suggesting a circulation error or a sensor fault.
Your boiler has tried to start several times but keeps losing its flame, causing the system to shut down for safety.
Your boiler's fan is not spinning at the correct speed to safely clear exhaust fumes, often due to a mechanical failure or a strong gust of wind blocking the flue.
Your boiler has sensed that the water returning from your radiators is hotter than the water leaving the unit, usually caused by a circulation problem or a sensor fault.
Your boiler has likely stopped heating because water isn't moving through the system properly or a vital internal sensor has lost its connection.
Your boiler has shut down because it the internal system is overheating, likely due to a blockage or a pump failure.
Your boiler is simply letting you know that the reset button has been activated and the system is restarting.
Your boiler has detected that there is not enough water in the system to operate safely and has shut down to prevent damage.
Your boiler’s internal computer has suffered a critical failure or a communication error and can no longer control the heating process.
Your boiler has lost signal between its internal computer and the gas control system, meaning it cannot safely light the flame to provide heating or hot water.
Your boiler's internal computer brain has detected a configuration setting error, likely caused by a component fault or an incorrect setup during a recent repair.
Your boiler's electronic control board has detected a configuration setting error, likely caused by a technical change or a fault in the internal wiring.
Your boiler's internal computer settings have been altered or are incorrect, preventing it from starting up properly.
Your boiler is having trouble communicating with external controls like your thermostat or programmer because of a potential wiring fault.
Your boiler is having trouble communicating with your thermostat or remote control system, meaning it cannot receive the command to turn on.
Your boiler has lost communication with the internal gas control system, meaning it cannot safely light the flame to provide heat or hot water.
Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit due to a sensor or wiring problem.
Your boiler has stopped working because it can no longer accurately measure the temperature of the water used for heating and hot water.
Your boiler has reached a critically high temperature because the water inside it is not moving quickly enough to carry the heat away.
Your boiler has detected an issue with the sensor that monitors exhaust gases and has shut down for safety.
Your boiler has detected an issue with a safety sensor that monitors exhaust gases, causing the system to shut down for protection.
Your boiler has overheated or detected dangerously hot exhaust gases, often because water isn't moving through the system correctly.
Your boiler has reached an unsafe temperature and has automatically shut down to prevent damage or overheating.
Your boiler has tried to ignite but failed, meaning your heating and hot water will not work until it is reset or repaired.
Your boiler incorrectly thinks it has lit a flame when it hasn't, or there is an electrical issue preventing it from starting safely.
Your boiler's fan has stopped spinning, which means it cannot safely clear away exhaust fumes and has shut down for safety.
Your boiler has detected an internal failure in the gas control parts and has locked itself out for safety.
Your boiler has detected an issue with the sensor that monitors internal water temperature, causing it to shut down to prevent overheating.
Your boiler has switched itself off because the water inside has become too hot, which is often caused by trapped air blocking the flow.
Your boiler is struggling to push water around your radiators, which is often caused by trapped air blocking the flow.
Your boiler's internal computer has developed a fault and is no longer able to control the heating process safely.
Your boiler is struggling to light its flame correctly, which means you have lost your heating and hot water.
Your boiler has lost communication with the gas control valve, meaning it cannot light the flame to provide heat or hot water.
Your boiler is having trouble communicating with the optional sensor used to measure the temperature outside, meaning it may not know how hard it needs to work to heat your home.
Your boiler has detected that water isn't moving through the system correctly, so it has shut down to prevent itself from overheating.
Your boiler is detecting that water is moving through the system even when the pump is supposed to be off, causing it to shut down for safety.
Your boiler's electronic control board is having trouble communicating with the internal gas valve, which has caused the system to shut down for safety.
Your boiler has lost its ability to accurately measure the temperature of the water used for your heating, causing the system to stop working for safety.
Your boiler has detected a problem with how it disposes of waste gases or a sensor error, causing it to shut down for safety.
Your boiler has lost its ability to accurately measure the temperature of the water returning from your radiators, often causing it to shut down for safety.
Your boiler has detected a problem with the sensor that monitors your hot water temperature, meaning it cannot heat water safely or accurately.
Your boiler has detected an issue with its exhaust or air supply, meaning it cannot burn gas safely and has shut down to protect you.
Your boiler is struggling to detect when you turn on your hot taps, which means you may have inconsistent or no hot water.
Your boiler's internal computer has lost its settings and no longer knows how to run the burner efficiently or safely.
Your boiler has lost track of the water pressure inside the system because the internal sensor is either broken or poorly connected, causing it to stop heating.
Your boiler's internal computer has lost contact with the main control panel, meaning the system can no longer talk to itself to manage your heating.
Your boiler has detected an error while trying to automatically adjust its burner settings to ensure safe and efficient heating.
Your boiler's internal computer brain is struggling to keep time or communicate with its memory, which prevents it from running your heating and hot water correctly.
Your boiler is overheating because the water isn't moving through the system quickly enough to take the heat away.
Your boiler has likely overheated, causing a safety sensor to automatically shut the system down to prevent damage.
Your boiler has stopped because there is too much water pressure in the system, which can happen if it was overfilled or if the filling loop was left open.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler has stopped working because the water pressure is too low for the system to run safely.
Your boiler is overheating because the water is not moving around the pipes properly.
Your boiler has lost its flame multiple times in a row and has locked itself out to prevent further malfunctions.
Your boiler is struggling to keep a steady flame lit while it tries to automatically adjust its settings, causing it to shut down for safety.
Your boiler has detected that the exhaust gases are too hot or the sensor monitoring them has failed, causing the system to shut down for safety.
Your boiler has sensed that the exhaust gases are too hot and has shut down as a safety precaution to prevent damage.
Your boiler has failed to light because it either cannot get enough gas or it cannot detect the flame it has sparked.
Your boiler is struggling to light because it is detecting a lack of gas during the ignition process.
Your boiler has stopped working because it cannot get a steady supply of gas or there is a communication problem with the gas control valve.
Your boiler has detected that the temperature sensors are giving conflicting readings, likely because water is not flowing through the system correctly.
Your boiler has detected a problem with the fan that clears exhaust gases, preventing the system from starting up for safety reasons.
Your boiler has stopped working because the fan that removes waste gases is not spinning at the correct speed or has failed completely.
Your boiler is having trouble measuring the temperature of your hot water because the internal sensor has developed a technical fault.
Your boiler has stopped working because it cannot correctly detect the water pressure in the system.
Your boiler's internal computer has developed a fault and is struggling to control the system correctly.
Your boiler's computer control board has encountered a software or electrical glitch that has caused the system to stop working for safety.
Your boiler is struggling to move water through the system properly before it starts the heating process, often caused by a blockage or a pump issue.
Your boiler is overheating because water isn't moving through the system properly, causing it to shut down to prevent damage.
Your boiler has detected an issue with the electrical power supply frequency, causing it to shut down for safety.
Your boiler is struggling to accurately measure the temperature of the water being heated for your taps, which usually means a sensor has failed.
Your boiler thinks a flame is burning even though it hasn't turned the gas on, causing it to shut down for safety.
Your boiler is not receiving enough electrical power to operate correctly, causing it to shut down for safety.
Your boiler is struggling to maintain the correct water pressure and is performing a temporary check to see if the system can stabilise.
Your boiler has lost its connection to the gas valve, meaning it cannot safely ignite to provide heating or hot water.
Your boiler is overheating because the water is not moving through the system fast enough or the sensors are misreading the temperature.
Your boiler is overheating or struggling to circulate water properly, causing it to shut down for safety.
Your boiler has shut down because it is getting too hot too quickly, likely due to water not flowing through the system properly.
Your boiler is struggling to move water through the pipes, which usually means there is a blockage or the pump has stopped working.
Your boiler is overheating because water isn't moving through the system quickly enough to be cooled down while it heats your water.
Your boiler's internal computer brain is blank and does not know how to operate the system, usually following a part replacement or power glitch.
Your boiler's computer memory has become confused about its own settings, often caused by a brief power interruption or a signal error.
Your boiler's computer memory has become confused or has lost its specific settings, preventing it from starting up correctly.
Your boiler has detected that the water pressure is too low or there is a leak somewhere in your heating system, causing it to stop working as a safety precaution.
Your boiler is struggling to communicate with its internal temperature sensors, which is preventing it from heating up correctly.
Your boiler's internal computer parts are struggling to talk to each other, which means the system cannot send the signals needed to start up.
Your boiler has lost its flame while it was running, meaning it can no longer heat your water or radiators.
Your boiler has no power and the control panel is completely blank, meaning it cannot start the heating process.
Your boiler has failed to light the flame after several attempts and has locked itself for safety.
Your boiler's internal electrical system is experiencing a communication fault, meaning the control board cannot talk to the key components properly.
BoilerFaultCodes