BoilerFaultCodes.com

Ideal Logic Max Heat 2 Fault Codes

Regular Natural GasLPG 12-30 kW 2022-present
GC Numbers: 41-751-0341-751-0441-751-0541-751-0641-751-07

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

Most common fault codes

4.2
Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
May be DIY safe · £100-£350
4.3
Your boiler is failing to light the gas to create heat, so the system has shut itself down for safety.
May be DIY safe · £100-£350
4.4
Your boiler has detected that there is not enough water pressure or water is not moving through the system properly to operate safely.
May be DIY safe · £100-280

All 35 fault codes

Code Severity Plain English
4.2 High Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
4.3 High Your boiler is failing to light the gas to create heat, so the system has shut itself down for safety.
4.4 High Your boiler has detected that there is not enough water pressure or water is not moving through the system properly to operate safely.
4.5 High Your boiler is failing to keep its flame lit, which means it cannot heat your home or water.
4.6 High Your boiler's fan, which safely pushes exhaust gases out of the flue, has stopped working correctly and is preventing the boiler from firing up.
4.7 High Your boiler detects a flame when it should be off, which is a safety error that prevents the system from starting up.
4.8 High Your boiler has lost its ability to measure the temperature of the water leaving the unit, meaning it cannot safely regulate the heat.
4.9 High Your boiler has detected an issue with a temperature sensor that monitors the water returning from your radiators, often resulting in the system shutting down for safety.
4.10 Low Your boiler has lost communication with the sensor that measures the temperature outdoors, which may cause your heating to run less efficiently.
4.11 High Your boiler is not providing central heating even though it may still be providing hot water.
4.12 Medium Your boiler is providing central heating as normal, but it is currently unable to heat your hot water.
4.13 High Your boiler has lost power or the screen has failed, meaning it will not operate and you cannot see any settings or status messages.
4.14 Medium Your boiler is providing hot water to your cylinder correctly, but the central heating for your radiators is not working.
4.15 Medium Your boiler is providing central heating for your radiators as normal, but is failing to heat your hot water tank or taps.
4.16 High Your boiler has lost power or is suffering from a complete electronic failure, meaning the control screen is unresponsive and the heating will not operate.
Blocked Flue/Condensate High Your boiler has stopped working because it cannot safely get rid of waste gases or excess water through its external pipes.
Fan Fault High Your boiler has stopped working because the internal fan, which safely clears exhaust fumes, is not running correctly.
Fd High Your boiler has stopped working because it cannot detect water moving through the system to keep it running safely.
Flame On Before Gas On High Your boiler incorrectly thinks it sees a flame before it has even started the ignition process, which is a safety error that prevents it from starting up.
Flame on before gas valve on High Your boiler has detected a flame when there shouldn't be one, which means the internal sensors or ignition parts are sending incorrect signals to the control board.
FLOW TEMPERATURE SETPOINT CANNOT BE INCREASED TO 80ºC Low Your boiler has been intentionally restricted by an installer to prevent the water from getting too hot, usually to protect your underfloor heating or plastic pipes.
Flow Thermistor Fault High Your boiler has detected an issue with the sensor that monitors the temperature of the water leaving the unit, causing it to shut down as a safety precaution.
Gas Valve Fault High Your boiler has detected an electrical issue with the gas control system and has shut down as a safety precaution.
NO CH OPERATION Medium Your boiler is not receiving a signal to turn on the heating, which is usually caused by an external control setting or a simple adjustment rather than a broken internal part.
No Water Flow High Your boiler has stopped working because the water pressure is too low or water isn't moving through the system correctly.
Outside Sensor Fault Low Your boiler has lost connection with the sensor that measures the temperature outside, meaning it may not heat your home as efficiently as usual.
PCB Fault High Your boiler's internal computer has suffered a critical failure and can no longer control the heating system safely.
PCB REPLACED High Your boiler has recently had its main control board replaced and simply needs to be reactivated to confirm the new part is working.
Pump Dry Run High Your boiler has detected that there is not enough water in the system for the pump to operate safely, causing it to stop to prevent damage.
Pump Fault High Your boiler is unable to circulate water around the system, meaning your heating and hot water will not work.
Return Thermistor Fault High Your boiler has detected an issue with a temperature sensor that monitors the water returning from your radiators, preventing the system from heating up safely.
Room Thermostat Fault High Your heating hasn't come on because your wall thermostat has run out of power and cannot send a signal to the boiler.
Service Due Low Your boiler is simply reminding you that its annual safety check and maintenance visit is now due.
Service Required Low Your boiler is simply reminding you that it has been over a year since its last professional health check and it is now due for an annual service.
Spare PCB Not Set High Your boiler's computer brain has been replaced or reset and needs to be told which specific model it is controlling before it can start working.

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