24 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Promax Ultra
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 →
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 |
|---|---|---|
| 41-601-17 | Promax 24/2 HE Plus | 2005–2010 |
| 41-601-22 | Promax 30 HE Plus | 2005–2010 |
| 41-605-52 | Promax 15/2 HE Plus | 2005–2010 |
Tap any card for details
Your boiler has stopped working because it cannot safely vent the exhaust gases, so it has locked itself to prevent unsafe operation.
Your boiler is failing to run because it isn't receiving enough electricity from your home's power supply.
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
The internal computer that controls your boiler has experienced a permanent error and is no longer able to give instructions to your heating system.
Your boiler's internal computer has developed a fault and is unable to operate, meaning the system will not provide any heating or hot water until a professional repairs it.
Your boiler has discovered a problem with the internal air ventilation system and has safely shut itself down to prevent unsafe operation.
Your boiler is not receiving enough electricity from your home's power supply to run safely and consistently.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent any internal damage.
The internal computer board inside your boiler has developed a fault and is failing to send the correct signals to start your heating and hot water.
Your boiler's central control computer has developed an internal electrical fault and is no longer able to give instructions to the system.
Your boiler has detected that water is not circulating properly through the system, so it has shut down to protect the internal components from overheating.
Your boiler has detected that the electricity cables supplying it have been wired the wrong way around, preventing it from operating safely.
Your boiler's internal computer has developed a fault and is failing to communicate with the rest of the unit, meaning it will not operate until repaired.
Your boiler has detected that it is running without enough water inside, which means it cannot safely heat your home and has shut itself down to prevent damage.
Your boiler has stopped working because a sensor that measures water temperature is providing incorrect information or has failed.
Your boiler has detected that the electrical wires providing its power have been connected the wrong way around.
Your boiler's internal electronic brain has detected a critical error and is unable to safely control the heating system, meaning the boiler has shut down.
Your boiler is having trouble detecting the temperature of the water used for your taps, which means it may struggle to provide consistent hot water.
Your boiler has stopped working because the internal fan, which safely exhausts gases, is unable to start or spin at the correct speed.
Your boiler has lost all power and is completely unresponsive as if it has been unplugged.
Your boiler has failed to light the flame properly and has shut itself down as a safety precaution while trying to start up.
Your boiler has lost its internal connection to the control panel, causing it to stop operating completely.
Your boiler has automatically shut down because it has detected that it is getting dangerously hotter than it should be.
Your boiler has detected a faulty temperature sensor which means it can no longer accurately monitor how hot the water is getting.
BoilerFaultCodes