54 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Promax Ultra System
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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 |
|---|---|---|
| 41-590-62 | Potterton Promax 24 HE | 2002–2005 |
| 41-591-89 | Promax SL 30 | 2007–present |
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Your boiler has attempted to start several times but cannot get the flame to stay lit, so it has locked itself for safety.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler has detected that it is running too hot and has automatically shut down to prevent damage, possibly due to a heat sensor issue or a problem with the internal gas supply.
Your boiler has detected an internal fault with its primary safety control switch, which is preventing the system from firing up safely.
Your boiler has detected an issue with how efficiently it is transferring heat, which has caused it to shut down for safety reasons.
Your boiler has detected that the water pressure in your heating system is too low to operate safely, so it has shut down to protect its internal components.
Your boiler has detected a flame even though the gas supply has been switched off, which suggests a potential safety issue with the internal gas controls.
Your boiler has detected a flame signal when it is not supposed to, meaning it is safer to stop using it while a professional checks the internal controls.
Your boiler's fan is not spinning at the correct speed to safely clear waste gases, so the system has locked out to keep your home safe.
Your boiler's internal computer is struggling to talk to the rest of the system, so it has safely shut down to prevent any further issues.
Your boiler is struggling to detect water moving through the system, which prevents it from safely heating your home.
Your boiler has detected that the water pressure in your central heating system is currently set too high for it to operate safely.
Your boiler has detected that the water inside is getting much hotter than it should be and has switched itself off to prevent damage.
Your boiler is failing to detect the flow of water because of a faulty connection or sensor, which prevents it from heating your home or hot water.
Your boiler's internal sensor that detects water movement has developed an electrical fault, causing the system to stop working as a precaution.
Your boiler has lost the signal from the sensor that monitors your hot water temperature.
Your boiler has detected a faulty connection in the component that monitors your hot water temperature, which means it has stopped heating your water to prevent potential system errors.
Your boiler has detected a flame even though it has commanded the gas supply to shut off, meaning it has safely locked itself to prevent a potential hazard.
Your boiler has detected that the electrical wires providing its power have been connected the wrong way around during installation or a recent electrical repair.
Your boiler is struggling because the electricity coming from your home’s mains supply is inconsistent or not vibrating at the steady frequency it requires to function safely.
Your boiler has detected a loose connection or a fault in its internal wiring, which is preventing it from starting up correctly.
Your boiler has lost the ability to read the temperature of the water returning to it, so it has safely shut down to prevent overheating.
Your boiler has lost the ability to accurately measure the temperature of the water returning to it, so it has safely shut down to prevent potential overheating.
Your boiler's computer is experiencing a temporary glitch and needs to be restarted to try and clear the error.
Your boiler has detected that the internal fan responsible for safely removing exhaust gases is not operating correctly, so it has shut down to keep your home safe.
Your boiler has detected an issue with the component that controls the gas flow, meaning it cannot safely ignite or maintain a flame to heat your home.
Your boiler's electronic control system is miscommunicating with its sensors, which prevents it from firing up safely to provide heating or hot water.
Your boiler is struggling to register that it has been turned on or is experiencing an internal communication error with its main control system.
Your boiler is failing to ignite because the component responsible for creating the spark to start the flame is not functioning correctly.
Your boiler is failing to detect the flame needed to heat your home, likely because the sensor responsible for confirming the fire has lit has become dirty or faulty.
Your boiler is failing to ignite because there is a fault with the electrical connection that creates the spark needed to start the flame.
Your boiler is failing to detect the flame correctly, so it has safely shut itself down to prevent gas from flowing without a flame present.
Your boiler is struggling to manage the pressure change as your heating water warms up, which usually indicates the internal vessel that absorbs this expansion needs to be recharged or replaced.
Your boiler has detected that the internal pressure relief mechanism has been triggered, which can be caused by the system pressure being too high or a faulty safety valve.
Your boiler is having trouble 'reading' the temperature of your hot water storage, which is preventing it from heating your water correctly.
Your boiler is having trouble measuring the temperature of the water used for your hot taps, which means it cannot provide hot water properly.
Your boiler has detected that it has become too hot and has automatically shut itself down to prevent any damage or safety hazards.
Your boiler's electronic brain is unable to read the water pressure level accurately due to a fault with the internal sensor.
Your boiler has detected a potential issue with the seals surrounding the gas components, which requires a professional inspection to ensure the system is operating safely and remains airtight.
Your boiler has detected a internal water leak or a compromised seal within the unit's plumbing components, which is causing it to stop运行 safely.
Your boiler's internal memory backup battery is running low, which means it may struggle to keep the correct time or save your heating schedule during a power cut.
Your boiler is struggling to light because the part responsible for creating the spark to start the flame is failing or worn out.
Your boiler is failing to detect a flame, which prevents it from safely igniting and providing you with heating or hot water.
Your boiler is struggling to direct hot water correctly between your radiators and your taps, which usually prevents the system from heating up properly.
Your boiler is having difficulty directing the flow of hot water between your radiators and your taps because a motorized component has failed.
Your boiler is not able to move the water around the system effectively, which is preventing your radiators and hot water from working properly.
Your boiler is struggling to get rid of trapped air inside the system, which is preventing it from running properly.
Your boiler has stopped working because an internal electrical fuse has blown, causing the system to lose power to its controls.
Your boiler has detected an issue with the water pressure coming into the system, meaning it cannot safely circulate or heat your water.
Your boiler is experiencing a communication error with its internal water pressure sensor, which prevents it from safely operating your heating or hot water.
Your boiler is struggling to accurately measure the water pressure inside the system because the sensor responsible for this reading has developed a fault.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler has stopped working because the water level inside the heating system has dropped below the required amount.
Your boiler has automatically shut down because the internal water pressure has climbed too high and exceeded safe operating limits.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes