BoilerFaultCodesThe 6 most common faults
Your boiler has tried to light itself but failed, meaning it has temporarily shut down for safety and won't provide heating or hot water.
Why it happens: This fault occurs when the boiler fails to detect a flame after several attempts to start up. The most common reasons include a lack of gas reaching the unit, a worn-out ignition spark electrode, or a faulty gas valve that isn't opening correctly. It essentially means the boiler is trying to light itself, but for one of these reasons, the fire simply won't catch.
Check if other gas appliances, like a cooker, are working to ensure gas is reaching the property.Turn the mode selector dial to the 'OFF/RESET' position, wait for five seconds, then turn it back to the original position.If it is freezing outside, check that your white plastic condensate pipe has not frozen solid.
Your boiler has switched itself off because it has become too hot, usually because water isn't moving through the system properly.
Why it happens: This fault occurs when the water inside the boiler exceeds a safe temperature limit, triggering a safety shutdown to prevent damage. The most common reason is that the internal pump has failed or is blocked, preventing the heat from being carried away to your radiators. It can also be caused by a build-up of limescale in the heat exchanger or air trapped within the system.
Turn the boiler off and wait at least 30 minutes for it to cool down.Check that your radiator valves are open and your system pressure is between 1 and 1.5 bar.Turn the control knob to the 'Reset' position, hold for a few seconds, then move it back to the 'ON' position.
Your boiler has detected a problem safely clearing waste gases through the flue pipe, which has caused the system to shut down for safety.
Why it happens: This fault occurs when the boiler's internal safety sensors detect that the fan isn't moving enough air to safely expel exhaust gases through the flue. The most common reasons are a failing fan motor, a blockage in the flue pipe, or a build-up of debris in the small plastic tubes that monitor air pressure. Because the boiler cannot guarantee that harmful fumes are being moved outside, it shuts down as a critical safety precaution.
Locate the mode selector switch on the front control panel.Move the switch to the 'OFF/RESET' position and wait for approximately 10 seconds.Move the switch back to either the 'Hot Water Only' or 'Heating and Hot Water' position to attempt a restart.
Your boiler has stopped working because the water pressure is too low for it to run safely.
Why it happens: This fault occurs when the internal water pressure drops below the minimum level required for the boiler to operate safely. The most common reason is a slow leak somewhere in your central heating system, though it can also happen if you have recently bled your radiators and haven't topped the pressure back up.
Locate the filling loop (the flexible silver hose) under the boiler.Slowly open the valve or valves on the loop until you hear water moving.Watch the pressure gauge until it reaches between 1 and 1.5 bar, then close the valves completely.Turn the control dial to the 'Reset' position and then back to your original setting.
Your boiler has experienced a lockout due to a failure to ignite or a flame being lost during operation.
Why it happens: This fault happens because the boiler has tried to light the burner but failed to detect a steady flame after several attempts. It is usually caused by a lack of gas reaching the burner, a worn-out ignition spark, or a sensor that can no longer 'see' the flame even if it is there.
Locate the mode selector switch on the front panel.Turn the switch to the 'OFF/RESET' position and wait for a few seconds.Turn the switch back to either 'Hot Water' or 'Heating and Hot Water' mode to restart the boiler.
Your boiler has switched itself off because its internal burner has become too hot to operate safely.
Why it happens: This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety sensor to shut the system down to prevent damage. It is usually caused by a lack of water flow, which often happens if the internal pump has failed or if there is a severe blockage in the main heat exchanger. In some cases, the sensor itself may have developed a fault and is incorrectly reporting that the unit is overheating.
Turn the mode selector switch to the 'OFF/RESET' position.Wait for approximately 30 seconds.Turn the switch back to either the 'Hot Water Only' or 'Heating and Hot Water' position.Ensure your radiator valves are open and the system pressure is between 1 and 1.5 bar.
on the Vokera Linea Plus AG
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