• 1. Error code F1
    If your boiler has shut down and is showing this error code, then the boiler has low water pressure. Add more water to the system.

    See the Check the pressure of your system topic for more information.
  • 2. Error code F2/FN
    If your boiler has shut down and is showing this error code, then the boiler has encountered an ignition failure. Check the gas supply to the property is switched on and that the supply hasn't been interrupted.
    • Visually confirm the main gas isolation tap is in the ON position (in newer houses this is normally found with the gas meter. Alternatively, it may be under the stairs, under the kitchen sink or possibly in the garage if you have one).
    • If you have a pre-pay gas meter, check that the money hasn't run out.
    • If you have another gas appliance in the property, switch this on to confirm the gas is being supplied correctly.
    • If your other gas appliances are working correctly, contact us to arrange an engineer visit.
  • 3. Error code F3
    If your boiler has shut down and is showing this error code, then there is a fault with the fan. Press the restart button to restart the boiler.

    If this does not correct the error contact us to arrange an engineer visit.
  • 4. Error code F4
    If your boiler has shut down and is showing this error code, then there is a fault with the water flow. Press the restart button to restart the boiler.

    If this does not correct the error contact us to arrange an engineer visit.
  • 5. Error code F5
    If your boiler has shut down and is showing this error code, then there is a fault with the return. Press the restart button to restart the boiler.

    If this does not correct the error contact us to arrange an engineer visit.
  • 6. Error code F6
    If your boiler has shut down and is showing this error code, then there is a fault with the weather sensor. Press the restart button to restart the boiler.

    If this does not correct the error contact us to arrange an engineer visit.
  • 7. Error code F7
    If your boiler has shut down and is showing this error code, then the voltage being supplied to the boiler is incorrect. Contact us to arrange an engineer visit.
  • 8. Error code F8/F9
    If your boiler has shut down and is showing this error code, then the PCB (the circuit board inside the boiler) has not been setup correctly. Contact us to arrange an engineer visit.
  • 9. Error code FA/FU
    If your boiler has shut down and is showing this error code, then there is a fault with the flow and return within the boiler. Press the restart button to restart the boiler.

    If this does not correct the error contact us to arrange an engineer visit.
  • 10. Error code FT
    If your boiler has shut down and is showing this error code, there is a fault with the opentherm connection (used with a smart thermostat). Check the batteries.

    If this does not correct the error contact us to arrange an engineer visit.
  • 11. Error code L1
    If your boiler has shut down and is showing this error code, then the boiler has low water pressure. Add more water to the system.

    See the Check the pressure of your system topic for more information.
  • 12. Error code L2
    If your boiler has shut down and is showing this error code, then the boiler has encountered an ignition failure. Check that the gas supply to the property is switched on and that the supply hasn't been interrupted.
    • Visually confirm the main gas isolation tap is in the ON position (in newer houses this is normally found with the gas meter. Alternatively, it may be under the stairs, under the kitchen sink or possibly in the garage if you have one).
    • If you have a pre-pay gas meter, check that the money hasn't run out.
    • If you have another gas appliance in the property, switch this on to confirm the gas is being supplied correctly.
    • If your other gas appliances are working correctly, contact us to arrange an engineer visit.
    • If the weather is cold, ensure the condensate pipe isn't frozen (see the Preventing a frozen condensate pipe topic for more information).
  • 13. Error code LN
    If your boiler has shut down and is showing this error code, then the boiler has lost it's flame. Check the gas supply to the property is switched on and that the supply hasn't been interrupted.
    • Visually confirm the main gas isolation tap is in the ON position (in newer houses this is normally found with the gas meter. Alternatively, it may be under the stairs, under the kitchen sink or possibly in the garage if you have one).
    • If you have a pre-pay gas meter, check that the money hasn't run out.
    • If you have another gas appliance in the property, switch this on to confirm the gas is being supplied correctly.
    • If your other gas appliances are working correctly, contact us to arrange an engineer visit.
  • 14. Error code L4
    If your boiler has shut down and is showing this error code, then there is a fault with the water flow. Press the restart button to restart the boiler.

    If this does not correct the error contact us to arrange an engineer visit.
  • 15. Error code L5
    If your boiler has shut down and is showing this error code, then there is a problem with the return temperature. Press the restart button to restart the boiler.

    If this does not correct the error contact us to arrange an engineer visit.
  • 16. Error code LC
    If your boiler is showing this error code, then your boiler has been reset 5 times in 15 minutes. Shut off the power to the boiler for 30 seconds and turn it back it on again.

    If this does not correct the error contact us to arrange an engineer visit.
  • 17. Error code L6
    If your boiler is struggling to ignite and is showing this error code, then your condensate pipe may be experiencing a false flame lockout. Press the restart button to restart the boiler.

    If this does not correct the error contact us to arrange an engineer visit.
  • 18. Error code L8/L9
    If your boiler has shut down and is showing this error code, then the PCB (the circuit board inside the boiler) has not been setup correctly. Contact us to arrange an engineer visit.
  • 19. For more useful information regarding Ideal boilers, take a look at these Ideal boiler videos and FAQs.

    If you have misplaced or lost your user manual, you can locate a replacement manual from this list of Ideal boilers (please have your model number to hand).
  • We update the maintenance tips and troubleshooting guidance from time to time and aim to make it as helpful as possible. The purpose of the maintenance and troubleshooting section of this website is to provide you with general guidance. Please ensure you read and follow our instructions carefully and do not undertake the maintenance or troubleshooting unless you are aged 18 or over, are competent to do so and are confident that you can complete the maintenance. If in doubt do not attempt any actions and where an appliance is gas fuelled refer to a Gas Safe engineer for assistance.

    This website is not intended to be a substitute for professional advice and does not:
    - cover every reason that your product could fail;
    - cover all of the maintenance that can be undertaken for your product;
    - supersede any advice in your instruction manual or from your product manufacturer.

    Do not carry out any maintenance or use the troubleshooting guide if it puts you or anyone else in danger or if you believe it may cause damage to your, or another person’s property.