BoilerFaultCodesThe 6 most common faults
Your boiler has failed to ignite and has locked itself out as a safety precaution.
Why it happens: This fault occurs when the boiler tries to light the flame several times but fails to detect one, causing it to shut down for safety. The most common reasons include a blocked gas supply, worn-out spark electrodes that can no longer ignite the gas, or a faulty internal component failing to open the gas valve.
Check if your gas supply is turned on and other gas appliances are workingRotate the mode selector switch to the 'Reset' position and wait for 10 secondsReturn the selector switch to the original position and wait for the boiler to restart
Your boiler has likely stopped working because it has overheated or detected a safety limit issue that it cannot automatically reset.
Why it happens: This fault occurs when the boiler's internal temperature exceeds a safe limit, causing the system to shut down to prevent damage. The most common reasons are a failed pump stopping water from circulating or a build-up of air and debris creating a blockage within the heat exchanger. It can also be triggered by a faulty sensor that is incorrectly reporting the temperature to the main control board.
Locate the mode selector switch on the front panelTurn the switch to the 'OFF/RESET' position and wait for a few secondsTurn the switch back to either the 'Hot Water' or 'Heating and Hot Water' position
Your boiler has failed to ignite after several attempts and has locked itself out for safety.
Why it happens: This fault occurs when the boiler's control system attempts to light the burner but fails to detect a stable flame after several tries. This is usually caused by a lack of gas supply, a worn-out component that creates the spark, or a sensor that is no longer able to tell the boiler that the fire has actually started.
Check that your gas emergency control valve is open and you have credit on your meter.Check if other gas appliances in your home are working correctly.Press the reset button (turn the selector switch to the 'R' position for a few seconds and then back to 'On').
Your boiler has shut down completely because it reached the maximum number of failed attempts to fix an underlying problem.
Why it happens: This fault occurs when the boiler's internal computer has tried multiple times to resolve a previous error but has failed to do so safely. It acts as a safety shutdown to prevent damage, usually triggered by a persistent issue with the ignition process or the fuel delivery system. Because the boiler cannot confirm it is firing correctly after several attempts, it enters a hard lock to protect the household.
Turn the mode selector switch to 'OFF/RESET' for 5 secondsTurn the dial back to the 'Hot Water' or 'Heating' positionMonitor the display to see if a different fault code (like 01 or 03) appears immediately after resetting
Your boiler has failed to fire up or complete its safety checks after several attempts and has now locked itself out for safety.
Why it happens: This fault occurs when the boiler's control system fails to detect a flame after multiple ignition attempts, causing the unit to shut down for safety. The most common reasons are a lack of gas supply to the burner, a build-up of soot on the ignition sensors, or a failure in the electrical signals sent by the main control board.
Locate the mode selector switch on the front panel.Turn the switch to the 'OFF/RESET' position and wait for 10 seconds.Turn the switch back to either 'Hot Water Only' or 'Heating and Hot Water' to see if the boiler restarts.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Why it happens: This fault occurs when the boiler's internal electronics detect a brief interruption or a glitch in the data being sent between sensors. The most common cause is a sensor that is starting to wear out or a small electrical disturbance on the main control board that makes the system pause to re-check its readings.
Locate the filling loop, which is usually a small silver braided hose with one or two valves underneath the boiler.Slowly open the valve(s) to allow cold mains water into the system while watching the pressure gauge on the front of the boiler.Stop filling once the needle reaches the green zone, typically between 1.0 and 1.5 bar, then ensure the valves are tightly closed.
on the Vokera Linea HE
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