BoilerFaultCodesThe 6 most common faults
01
F01 High DIY-safe
Your boiler has locked out due to low water pressure in the system, meaning it has temporarily stopped working to protect itself.
What to try first
Locate the filling loop underneath your boiler.Open the valves slowly until the pressure gauge on the front of the boiler rises to between 1.0 and 1.5 bar.Close the valves firmly and press the reset button on the boiler.
02
L2 High DIY-safe
Your boiler has tried to light five times in a row and failed, so it has safely locked itself off to prevent a build-up of gas.
What to try first
Check if your gas supply is working by testing another gas appliance like a cooker.Check your gas prepayment meter to ensure you have credit if applicable.Press the reset button on your boiler for up to 5 seconds to try restarting the ignition process.
03
L01 High Engineer
Your boiler has stopped working safely and is locked out, but the specific reason is shown by the number following the letter 'L' on your display.
Full guide for L0104
L 02 High Engineer
Your boiler has failed to light the flame, so it has safely shut itself down to prevent any unburned gas from building up.
Full guide for L 0205
F 02 High Engineer
Your boiler has lit up but the flame has unexpectedly gone out, causing the system to stop working as a safety precaution.
Full guide for F 0206
F 03 High Engineer
Your boiler has detected an issue with its internal air extraction system, which is preventing it from safely lighting and operating.
Full guide for F 03on the Ideal INDEPENDENT COMBI2
Pressure relief valvePressure sensorAutomatic air ventIgnition electrodeGas valvePCB
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Ideal shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue
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