BoilerFaultCodesThe 6 most common faults
Your boiler has failed to light or maintain a flame, which means it has locked itself out to prevent fuel from building up.
Why it happens: This fault occurs when the boiler tries to light but cannot establish a stable flame to provide heat or hot water. The most common reasons include a lack of gas reaching the burner, a buildup of carbon on the ignition probe, or a faulty component that is unable to detect that the fire has actually started. To stay safe, the boiler stops working immediately to ensure gas does not enter your home without being burned.
Check if other gas appliances (like a cooker) are working to confirm gas is reaching the propertyTurn the selector switch to the 'R' (Reset) position for a few seconds and then back to the 'ON' positionEnsure your gas meter has credit if you are on a pre-payment meter
Your boiler has stopped working because it has gotten too hot or the water is not circulating through the system correctly.
Why it happens: This fault occurs when the internal temperature of the boiler rises too quickly or exceeds a safe limit, triggering a safety shut-off. It is usually caused by a physical blockage in the pipework, a mechanical failure of the pump, or air trapped within the heat exchanger that prevents heat from being carried away. Essentially, the water is not moving through the boiler fast enough to keep it cool.
Wait for the boiler to cool down for at least 30 minutes.Check that all radiator valves and the flow/return valves under the boiler are fully open.Press the 'Reset' button on the front control panel to restart the unit.
Your boiler has detected that the water pressure is too low for it to operate safely, which is usually caused by a small leak or air in the system.
Why it happens: This fault occurs when the internal water pressure drops below the minimum level required for the boiler to circulate heat safely. The most common reason is a small leak in the radiator network or air being released through the valves, which gradually reduces the volume of water in the system.
Check the pressure gauge on the front of the boiler; it should ideally be between 1 and 1.5 bar.Locate the external filling loop (the silver flexible hose) underneath or near the boiler.Slowly open the valves on the filling loop until you hear water entering and the needle reaches 1.5 bar, then close them tightly.
Your boiler has lost its connection with the external remote controller, meaning they are unable to talk to each other to manage your heating.
Why it happens: This fault occurs when the boiler's main internal computer loses its digital handshake with the wall-mounted remote control unit. The most common reason is a loose connection in the wiring between the two devices or a component failure within the remote control unit itself that stops it from sending or receiving signals. Without this vital link, the boiler cannot receive instructions on when to turn the heating on or off.
Check if the batteries in your RC05 remote control unit need replacingEnsure the remote control is within range of the boiler and has not been movedTurn the boiler power off and back on again to try and reset the connection
Your boiler has detected a blockage or a fault in the system that expels exhaust gases, causing it to shut down for safety.
Why it happens: This fault occurs when the boiler's safety sensors detect that harmful exhaust gases are not being cleared from the system effectively. The most common reasons are a buildup of dirt or debris in the small tubes inside the boiler, a failing fan that cannot spin fast enough, or a blockage within the external flue pipe.
Full guide for 03Your boiler has lost its ability to accurately measure the water temperature inside the system, which is preventing it from heating up safely.
Why it happens: This fault occurs when the internal sensor responsible for monitoring water temperature fails or loses its connection to the main control board. The most common reason is that the sensor has simply worn out over time or the electrical pins have become corroded, preventing the boiler from knowing if the water is getting too hot. Because the boiler can no longer monitor safety temperatures, it shuts down to prevent any internal damage.
Full guide for 07on the Vokera Linea 28
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