BoilerFaultCodesThe 4 most common faults
Your boiler has overheated, causing it to shut down automatically for safety.
Why it happens: This fault occurs when the internal temperature of the boiler exceeds a safe limit, triggering a safety sensor to cut the power to prevent damage. The most common reasons are a blockage in the system or a pump failure, which stops the water from moving quickly enough to carry heat away from the burner.
Check that at least one radiator or bypass valve is fully openTurn the selector switch to the 'OFF/RESET' position for 10 secondsTurn the selector switch back to 'ON' and check if the red light stops flashing
Your boiler has failed to light the gas flame and has shut down as a safety precaution.
Why it happens: This fault occurs when the boiler attempts to start up but cannot detect a sustained flame, leading it to shut down for your safety. The most common reasons include a lack of gas reaching the unit, worn-out spark electrodes that can no longer ignite the fuel, or a faulty sensor that fails to 'see' the flame even if it is lit.
Check that your gas supply is turned on and other gas appliances are workingRotate the control knob to the 'OFF/RESET' position and then back to the 'ON' positionWait for the boiler to attempt to restart; if the red light remains, a professional is required
Your boiler has detected an issue with the way it is venting or drawing air, which has safely stopped the unit from firing up.
Why it happens: This fault occurs when the boiler's internal safety sensors detect that the fan isn't moving enough air to safely carry away exhaust fumes. The most common reason is a blockage in the flue pipe or a buildup of debris in the small tubes that measure air pressure, which prevents the boiler from firing for your safety.
Full guide for Flashing yellowYour boiler is working normally and is simply indicating that a hot water tap is currently turned on somewhere in your home.
Why it happens: This status occurs when the boiler detects water flowing through the domestic hot water pipework. A flow switch inside the unit senses the movement of water and signals the burner to ignite in order to heat the water for your shower or taps. It is a sign of normal operation rather than a mechanical failure.
Check that all hot water taps are fully closedEnsure there are no leaking hot water taps or dripping showersMonitor the lights; the red light should remain off and the green light will stay on while water is running
on the Vokera Aquanova
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 Vokera 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