129 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Potterton Promax
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 turning off because your home is warm enough.
Your boiler has detected that it is getting too hot or the water isn't moving through the system correctly, causing it to shut down for safety.
Your boiler has become too hot and has automatically shut down for safety purposes.
Your boiler has momentarily lost its flame and is trying to restart itself, which often indicates a minor interruption in the gas supply or a slightly dirty component.
Your boiler has tried to light itself several times but cannot establish a flame, meaning your heating and hot water will not work.
Your boiler has temporarily lost communication between its internal electronic parts but should automatically try to restart itself shortly.
Your boiler's internal safety system has detected that the fan responsible for clearing exhaust gases is not working correctly, preventing the boiler from starting.
Your boiler has experienced a brief communication glitch with its internal computer brain, which it should fix by itself automatically.
Your boiler's computer has lost its settings or is failing to communicate with its memory chip, causing the system to stop working.
Your boiler has encountered a minor temporary glitch and is currently attempting to restart itself automatically.
Your boiler has detected a general internal fault that is preventing it from firing up safely, often caused by a component failing to communicate properly.
Your boiler's fan, which safely clears waste gases away, is not starting up or spinning at the correct speed.
Your boiler has detected that the incoming electrical supply is too weak to power the system safely.
Your boiler has got too hot and has shut itself down as a safety precaution to prevents damage.
Your boiler's internal computer brain has developed an electronic fault and can no longer control the heating process safely.
Your boiler's internal computer has developed a fault and can no longer control the heating process safely.
Your boiler is struggling to move water around the system or has detected heat with no water present, causing it to shut down to prevent overheating.
Your boiler has detected a problem with its temperature sensor and has stopped running to prevent overheating.
Your boiler has detected that the electrical wiring coming into the unit is connected incorrectly, meaning the power flow is backwards.
Your boiler's internal computer has developed a fault and is unable to manage the system 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 it, which is putting excess stress on the internal pipework and safety valves.
Your boiler has stopped working because there is not enough water pressure in 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 water is not moving through the system properly, causing it to overheat and shut down for safety.
Your boiler hasn't been able to heat the water hot enough to kill off harmful bacteria within the storage tank.
Your boiler started to heat up but the flame went out unexpectedly while it was running.
Your boiler is failing to light the gas flame and has locked itself out for safety.
Your boiler has likely experienced a technical internal error or a safety lockout that has been manually cleared, but the system is now failing to restart correctly.
Your boiler's fan has failed to start or isn't running at the correct speed, which prevents the boiler from safely clearing out exhaust fumes and starting the ignition process.
Your boiler has stopped working because the fan cannot safely push waste gases out through the flue pipe.
Your boiler has detected an issue with how water is flowing through the system, preventing it from heating up safely.
Your boiler is unable to safely clear away waste gases, so it has stopped running to prevent a build-up of fumes.
Your boiler has detected that there is not enough water circulating inside it, causing it to overheat rapidly and shut down to prevent damage.
Your boiler has detected an electrical safety issue where the internal components are not properly grounded, causing the system to shut down for protection.
Your boiler has shut down because it has detected that the internal water temperature is far too hot and needs to cool down for safety.
Your boiler has detected that a small internal thermometer that monitors water coming back into the system is disconnected or faulty, causing the unit to stop working for safety.
Your boiler has stopped working because it cannot correctly read the temperature of the water returning to the unit due to a faulty or disconnected sensor.
Your boiler is confused because the water coming back from your radiators seems hotter than the water leaving the boiler, which usually means water isn't moving through the system correctly.
Your boiler is struggling to keep its flame lit and has locked itself out for safety after multiple failed attempts.
Your boiler's fan is not spinning at the right speed to safely clear waste gases, likely 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 boiler, which usually means the water isn't circulating correctly.
Your boiler has stopped working because water is not moving through the system properly or a sensor has lost connection.
Your boiler has become too hot and has shut itself down as a safety precaution, usually because water isn't moving through the system correctly.
Your boiler is simply notifying you that the reset button was recently held or pressed, which can sometimes happen during a manual restart or testing.
Your boiler has stopped working because there is not enough water pressure in the system to run safely.
Your boiler's internal computer has suffered a serious electronic failure and can no longer control the heating process safely.
Your boiler has lost the internal connection between its main control board and the gas system, meaning it cannot safely light the burner to provide heat.
Your boiler's internal computer settings have been altered or are incorrect, preventing it from starting up properly.
Your boiler's internal computer settings have been changed or detected incorrectly, which is preventing it from running properly.
Your boiler's internal computer settings have been altered or are mismatched, preventing the system from starting correctly.
Your boiler is having trouble communicating with external controls like your thermostat or timer due to a wiring issue.
Your boiler is having trouble communicating with your thermostat or wireless receiver, which often happens when the connection signal is lost or the devices need re-pairing.
Your boiler has lost communication with the internal valve that controls the gas supply, meaning the system cannot fire up to provide heating or hot water.
Your boiler has stopped working because it cannot correctly measure the temperature of the water moving through the system.
Your boiler has stopped working because it cannot communicate with the sensor that monitors the temperature of the water flowing to your radiators.
Your boiler has overheated because water is not moving through the system properly or at all.
Your boiler has identified an issue with the sensor that monitors exhaust gases, and it has shut down as a safety precaution.
Your boiler has stopped working because it cannot correctly measure the temperature of the exhaust gases leaving the system.
Your boiler has shut down because it is getting too hot inside, which is likely caused by water not moving through the system correctly or a faulty internal sensor.
Your boiler has reached an unsafe temperature and has automatically shut down to prevent damage or overheating.
Your boiler has failed to ignite, meaning it is unable to create a flame to provide heating or hot water.
Your boiler detects a flame when there shouldn't be one, or the internal burner is overheating, causing the system to shut down for safety.
Your boiler has stopped working because the fan that clears away waste gases is jammed or cannot spin properly.
Your boiler has detected a serious problem with how it controls gas or air, and has locked itself out for safety.
Your boiler has detected an issue with the sensor that monitors internal heat, which stops it from running safely and providing heating or hot water.
Your boiler has become too hot and has shut down as a safety precaution to prevent damage.
Your boiler is struggling to move water around the system effectively, which is usually caused by trapped air or a blockage.
Your boiler's internal computer has developed a fault and can no longer control the heating system safely.
Your boiler is struggling to light and stay on, which can sometimes be caused by air trapped in your heating system.
Your boiler has lost its connection to the gas control valve, meaning it cannot safely ignite to provide heat or hot water.
Your boiler is struggling to work out how hard to run because the sensor that monitors the weather outside has stopped sending a clear signal.
Your boiler has detected that water is not circulating properly through the system, preventing it from firing up for safety.
Your boiler has detected that a internal water pressure switch is stuck or blocked, preventing the unit from starting the ignition process for your heating.
Your boiler has detected a communication problem with the gas valve, meaning it cannot safely trigger a flame to provide heat or hot water.
Your boiler is struggling to accurately measure the temperature of the water flowing to your radiators, which prevents it from heating your home safely.
Your boiler has detected a problem with how it disposes of waste gases, which could be caused by a sensor fault or a physical blockage.
Your boiler has detected an issue with the sensor that monitors the temperature of the water coming back from your radiators, preventing it from heating correctly.
Your boiler's temperature sensor for hot water is giving an incorrect reading or has failed, meaning the system cannot safely heat your water to the right temperature.
Your boiler is struggling to breathe properly because the exhaust outlet outside your home might be obstructed, causing poor burning conditions.
Your boiler is struggling to detect when you turn on a hot tap, meaning you are likely getting cold water or inconsistent temperatures.
Your boiler’s internal computer has lost its timing settings and needs to be professionally synchronised to burn gas safely and efficiently.
Your boiler is struggling to accurately measure its internal water pressure, which means it cannot tell if it is safe to start or keep running.
Your boiler's internal computer has lost its connection with the control panel or external thermostat, meaning it cannot receive instructions to turn on.
Your boiler has detected an issue with the air and gas mixture while trying to automatically adjust its settings and has shut down to ensure safety.
Your boiler's internal computer has lost track of the correct time, preventing it from following your heating schedule.
Your boiler is struggling to move water through the system properly, which is causing it to stop running to prevent overheating.
Your boiler has likely overheated, causing a safety sensor to automatically shut the system down to prevent damage.
Your boiler has too much water in the system, which is causing it to shut down to prevent damage from overpressure.
Your boiler has stopped working because the water pressure in the system has dropped too low and needs to be topped up.
Your boiler has stopped working because the water pressure is too low for the system to run safely.
Your boiler is unable to move hot water around the system effectively, causing it to shut down to prevent overheating.
Your boiler is repeatedly struggling to keep its burner lit, causing it to shut down for safety after 12 failed attempts.
Your boiler is struggling to keep its flame lit during its startup and setup phase, causing it to shut down for safety.
Your boiler has detected that the exhaust gases are getting too hot and has shut down to prevent internal damage.
Your boiler has shut down because it has detected that the exhaust gases are becoming too hot, which is a safety feature to prevent damage to the system.
Your boiler is failing to light because it either cannot get enough gas or the system is not detecting a flame.
Your boiler is trying to light but cannot detect a flame, meaning it is failing to ignite properly after multiple attempts.
Your boiler has stopped working because it cannot detect a steady flow of gas, which is likely due to an internal part failure or a supply issue.
Your boiler has noticed that water is not circulating correctly or the temperature sensors are disagreeing with each other.
Your boiler has stopped working because the fan that removes waste gases cannot spin at the correct speed or communicate with the main controls.
Your boiler has detected a problem with the fan that safely pushes waste gases out of your home, causing the system to shut down for safety.
Your boiler is unable to read the temperature of your hot water properly, which means your taps and showers likely won't get warm.
Your boiler is having trouble measuring its internal water pressure, which means it will stop running to protect the system.
Your boiler's internal computer has developed a fault and is struggling to communicate with the rest of the unit.
Your boiler’s internal computer has encountered a memory or software error and has stopped working to protect itself.
Your boiler is struggling to move water around the system properly before it begins the full heating process.
Your boiler has detected that water isn't moving through the system properly, causing it to overheat quickly as if it were running dry.
Your boiler has detected that the electricity coming from your mains supply is at the wrong frequency, preventing it from running safely.
Your boiler's hot water sensor has failed or is sending an incorrect reading, meaning the system cannot safely monitor the temperature of your water.
Your boiler thinks a flame is present even when it hasn't been told to ignite, which is a safety conflict that prevents the system from starting.
Your boiler is not receiving enough electrical power to operate safely, which is usually caused by an external power cut or an internal electrical failure.
Your boiler is checking if there is enough water pressure to operate safely and has paused briefly to confirm the system is stable.
Your boiler has lost its connection to the internal gas control valve, meaning it cannot safely ignite to provide heating or hot water.
Your boiler is shutting down because the water inside is heating up too quickly or isn't moving through the pipes fast enough.
Your boiler is struggling to move water around the system properly, causing it to heat up much faster than it should and shut down for safety.
Your boiler has shut down temporarily because its internal temperature has risen too high or the water is not moving through the system quickly enough.
Your boiler is struggling to move water through the system, which is causing it to stop running to prevent overheating.
Your boiler is heating up too quickly and has shut down temporarily to prevent overheating, likely because water isn't moving through the system fast enough.
Your boiler's internal computer brain hasn't been set up correctly or has lost its memory, so it doesn't know how to operate.
Your boiler has stopped working because its internal computer settings have become scrambled and don't match the specific model requirements.
Your boiler's computer memory has become confused about its internal settings and cannot operate as intended.
Your boiler has detected that the water pressure is either too low or there is a leak somewhere in the heating system, causing it to stop for safety.
Your boiler is having trouble reading the temperature accurately due to a connection or sensor problem, causing it to stop running for safety.
Your boiler's main control center and display screen have stopped talking to each other, preventing the unit from starting up.
Your boiler has lost its flame while it was running, meaning it cannot provide heat or hot water safely.
Your boiler has no power and is completely unresponsive, meaning the control lights are not turning on at all.
Your boiler has failed to light several times and has locked itself out for safety.
Your boiler has detected an internal electrical communication problem between its main control components.
BoilerFaultCodes