BoilerFaultCodes.com

Ideal Boiler Fault Codes

Oil Natural Gas

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Most common fault codes

C0
Your boiler's internal computer chip has lost connection or failed to communicate with the main control board, preventing the system from starting.
May be DIY safe · £180-350
C2
Your boiler's internal memory card has developed a communication fault, meaning the control system cannot verify the specific settings for your model.
Gas Safe engineer required · £120-£350
F1
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
May be DIY safe · £0-120

All 18 fault codes

Code Severity Plain English
0 Low Your boiler is working perfectly and is simply waiting for you to turn on your heating or hot water.
C Low Your boiler is working exactly as it should and has simply paused because the water has reached the target temperature you set.
C0 High Your boiler's internal computer chip has lost connection or failed to communicate with the main control board, preventing the system from starting.
C2 High Your boiler's internal memory card has developed a communication fault, meaning the control system cannot verify the specific settings for your model.
D Low Your boiler has paused heating the water because it has already reached the target temperature you selected on the control dial.
F Low Your boiler has sensed a drop in temperature and is temporarily heating itself up to prevent the internal pipes from freezing.
F1 High Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
F2 High Your boiler has started to fire up but the flame has gone out, meaning the system has shut down for safety.
F3 High Your boiler has detected an issue with the part that pushes waste gases out of your home, causing the system to shut down for safety.
F4 High Your boiler has stopped working because it cannot accurately measure the temperature of the water flowing through the system.
F5 High Your boiler has lost its ability to monitor the temperature of the water returning from your radiators, often causing it to shut down to prevent damage.
F6 Low Your boiler has lost connection with the sensor that monitors the outdoor temperature, which might make your heating less efficient.
F7 High Your boiler has detected that the electrical supply coming into your home is too low for it to operate safely.
F9 High Your boiler’s internal computer brain hasn't been programmed correctly, meaning it doesn't know which model it is and cannot start up.
L1 High Your boiler has become too hot or water is not moving through the system properly, causing the unit to shut down for safety.
L2 High Your boiler has lost its flame while running or failed to light, meaning it has shut down for safety and won't provide heat or hot water.
L5 High Your boiler has been manually reset too many times in a short window of time as it tries to clear a persistent underlying fault.
L6 High Your boiler thinks a flame is present when it should be off, which is a safety lockout preventing the unit from starting.

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