BoilerFaultCodes.com

Ideal Maximiser SE Fault Codes

Regular Natural Gas 11.72-23.44 kW 2001-2007 Discontinued
GC Numbers: 41-392-1541-392-1641-392-1741-409-1541-409-17

Replaced by: Logic Heat

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Most common fault codes

1
Your boiler has sensed that the internal temperature around the burner or flue gases has become too high, causing it to shut down for safety.
Gas Safe engineer required · £120-280
1C
Your boiler has detected that a safety sensor meant to monitor exhaust gases is disconnected or has failed, causing the system to shut down for protection.
Gas Safe engineer required · £120-220
2
Your boiler has detected that water is not circulating correctly through the system to keep it cool.
May be DIY safe · £120-350

All 86 fault codes

Code Severity Plain English
-. H Low Your boiler is working correctly and is currently providing heat to your radiators.
=. H Low Your boiler is currently working as it should to provide hot water to your taps or shower.
0 Low Your boiler is currently idle and waiting for a command to provide heating or hot water, meaning it is working exactly as it should.
0A Low Your boiler is temporarily pausing between firing cycles to prevent the system from turning on and off too frequently, which protects the internal components from unnecessary wear.
0H Low Your boiler is working perfectly and is currently sitting in standby mode because it has already reached the required temperature.
0L Low Your boiler is currently trying to light the flame to start provide heating or hot water, which is a normal part of its startup sequence.
0U Low Your boiler is performing a routine safety check by blowing air through the system to clear any leftover gases before or after it fires up.
0Y Low Your boiler has paused briefly because the water inside has reached its maximum set temperature and is waiting for it to cool down before firing up again.
1 High Your boiler has sensed that the internal temperature around the burner or flue gases has become too high, causing it to shut down for safety.
1C High Your boiler has detected that a safety sensor meant to monitor exhaust gases is disconnected or has failed, causing the system to shut down for protection.
2 High Your boiler has detected that water is not circulating correctly through the system to keep it cool.
2C High Your boiler has shut down because a safety sensor has detected that the internal heat exchanger is getting too hot.
2F Medium Your boiler has detected that there is not enough water circulating through the system or that the water is heating up too quickly.
2P High Your boiler is overheating because the water inside it is getting too hot too quickly, causing the system to shut down for safety.
2U High Your boiler has detected that water is leaving the unit much hotter than it is returning, which usually means the water isn't circulating through your radiators fast enough.
4 High Your boiler has stopped working because it has detected that the water inside is getting too hot.
4A High Your boiler has shut down because a sensor has detected that the water inside is getting too hot.
4C High Your boiler has shut down because it has detected it is getting too hot or an internal safety fuse has blown.
4F High Your boiler has reached an unsafely high temperature and has shut down to prevent damage or overheating.
4L High Your boiler has detected an electrical fault with one of its main internal temperature sensors, causing the system to shut down for safety.
4P High Your boiler has lost its connection to an internal safety sensor and has shut down as a precaution to prevent damage.
4U High Your boiler has stopped working because an internal temperature sensor has developed an electrical fault and can no longer read the heat levels correctly.
4Y High Your boiler has lost its connection to the internal thermometer that monitors water temperature, meaning it cannot safely heat your home or water.
5 High Your boiler's internal components are having trouble talking to each other, which has caused the system to stop working for your safety.
5A Low Your boiler’s control panel has been locked manually or due to a button sequence error, preventing you from changing any settings.
5Y Low Your boiler’s control panel has become locked or entered a restricted mode, preventing you from changing any settings or operations.
6 High Your boiler is failing to detect a flame after it tries to ignite, meaning it will not stay lit to provide heat or hot water.
6A High Your boiler is failing to light the gas flame properly, meaning it cannot heat your water or radiators.
6C Emergency Your boiler is still detecting a flame even after it should have turned off, which suggests gas may still be flowing into the unit when it shouldn't be.
6H High Your boiler is lighting up but the flame goes out straight away, preventing the system from producing heat.
6L High Your boiler is successfully lighting, but it cannot stay lit and keeps cutting out while it is running.
7 High Your boiler has detected an issue with the electrical power supply coming from your mains, which is preventing it from running safely.
7A High Your boiler's main internal computer has developed a fault and is no longer able to control the heating process.
7C Medium Your boiler has lost power while trying to clear an old error, or the reset button wasn't held down for long enough.
7F High Your boiler's internal computer has lost power or suffered a hardware failure, meaning it cannot control the heating or hot water functions.
7H High Your boiler's main internal computer has developed a fault and is unable to control the heating system correctly.
7L High Your boiler's internal computer has developed a fault and is unable to send the correct signals to start the heating process.
8 High Your boiler is failing to ignite or detect a flame because there is an issue with the gas supply or the gas valve inside the unit.
8L High Your boiler has lost its connection to an internal sensor or controller, meaning it cannot communicate properly to start the heating process.
9 High Your boiler has detected an internal communication failure between its main control boards, meaning it can no longer send or receive the signals needed to operate.
9A High Your boiler's main internal computer has developed a fault and is no longer communicating correctly with the rest of the system.
9C High Your boiler's main control board has lost communication with its internal memory chip, meaning it cannot process the settings needed to run safely.
9F High Your boiler's internal computer is having trouble measuring its own temperature, which prevents it from operating safely.
9H High Your boiler's internal computer has suffered a technical failure and cannot communicate with the rest of the system.
9L High Your boiler has stopped working because of an internal communication error between the main control board and the gas valve.
9P High Your boiler's computer brain has suffered a serious internal electronic failure and can no longer communicate with the heating system.
9U High Your boiler's main control computer is unable to communicate with its internal memory chip, meaning it cannot access the settings needed to run safely.
18 High Your boiler is struggling to breathe properly because there is a blockage or too much debris in the air intake or exhaust system.
19 High Your boiler has stopped working because the fan that helps remove waste gases is not spinning or communicating correctly with the system.
20 High Your boiler has stopped working because it cannot properly measure the temperature of the water coming back into the system.
21 High Your boiler has shut down because a safety sensor has detected that the burner area is getting too hot or is failing to register a secure connection.
22 High Your boiler has lost power to a key internal safety part due to an electrical fault, meaning it cannot safely ignite to provide heating or hot water.
23 High Your boiler has stopped working because its internal sensors or control system have detected a technical communication error.
24 High Your boiler has lost communication with one of its internal sensors, meaning it cannot accurately monitor temperatures to run safely.
25 High Your boiler is unable to create a spark to light the gas, meaning your heating and hot water will not work.
26 High Your boiler has shut down because the mixture of gas and air required for a safe flame is incorrect, often due to a blockage or a dirty internal component.
27 High Your boiler is unable to light the flame because the gas supply is blocked or a safety sensor is cutting out.
28 High Your boiler is not receiving a steady supply of gas or has air trapped in the pipes, preventng the flame from lighting properly.
29 High Your boiler has failed to detect a flame, which means it cannot stay on safely and has stopped working for your protection.
30 High Your boiler has detected an issue with the electrical power supply to the unit while it was running.
31 High Your boiler has experienced an internal electrical short circuit which has likely blown a protective fuse, causing it to stop working entirely.
32 Medium Your boiler has experienced a temporary software or ignition glitch and simply needs to be rebooted to clear the error.
33 High Your boiler is not receiving enough gas to function properly, which means it cannot fire up safely or consistently.
34 Emergency Your boiler has detected that gas is potentially still flowing or a flame signal is present when it should be turned off, which is a safety concern.
35 High Your boiler's internal control module is failing to communicate with the fan, causing the system to shut down immediately after trying to start.
36 High Your boiler has detected a problem with how it monitors gas supply pressure, meaning it cannot safely confirm there is enough fuel to stay lit.
37 High Your boiler's internal communication chip is either faulty or has come loose, causing the system to stop working.
38 High Your boiler has stopped working because it has lost a secure electrical connection to the valve that controls the gas supply.
39 High Your boiler has lost communication with your wall thermostat, meaning it cannot receive the signal to turn on your heating.
40 High Your boiler has lost its electrical power supply or there is a fault with the incoming electricity to the unit.
41 High Your boiler’s internal control system has encountered a critical electronic failure that it cannot clear itself.
42 Medium Your boiler is producing more heat than your hot water tank can safely handle, causing the system to stop for protection.
43 Medium Your boiler is struggling to control how much water flows through the system, which can prevent it from heating up correctly.
44 High Your boiler has detected an electrical connection issue or a safety sensor has tripped to prevent the exhaust gases from getting too hot.
c Low Your boiler is simply running a quick self-test of its internal computer memory as it starts up.
d Low Your boiler is not currently experiencing a fault; it is simply performing a routine data check or start-up sequence.
E High Your boiler's computer brain has encountered a serious communication error and cannot tell the system how to operate safely.
EA High Your boiler’s internal computer has developed a fault and can no longer communicate with the rest of the system, causing it to stop working.
EC High Your boiler's internal computer has developed a fault and is unable to manage the heating system correctly.
EF High Your boiler's main internal computer has developed a fault and can no longer control the heating system correctly.
EH High Your boiler’s main control screen or internal computer has developed a fault and can no longer communicate with the rest of the system.
EL High Your boiler’s main computer screen or internal control board has developed a fault and is no longer communicating correctly with the rest of the system.
EP High Your boiler's internal computer parts are unable to talk to each other correctly because they are not compatible.
P Low Your boiler is currently going through its normal automatic startup and self-test sequence.
r Low Your boiler is simply going through a self-check and rebooting itself after you pressed the reset button.
Y Low Your boiler has been manually put into a service test mode and is currently locked at a low power setting for an engineer to take measurements.

Ideal Maximiser SE is discontinued — time for a new one?

Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.

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