BoilerFaultCodesThe 6 most common faults
Your boiler has detected a safety issue with its internal sensors or temperature controls and has shut itself down to prevent potential damage.
Why it happens: This fault occurs when the boiler tries to ignite but fails to create a stable flame, causing the system to shut down for safety. The most common reasons are a worn-out ignition spark, a blocked gas supply, or an internal sensor failing to detect that the burner has actually lit. In some cases, a fault with the main control board means the boiler isn't sending the correct signal to start the ignition process.
Check that your gas prepayment meter has creditEnsure other gas appliances in your home are working to confirm gas supplyPress the Reset button or turn the dial to 'OFF/RESET' and back to 'ON'
Your boiler has lost water pressure and needs to be topped up to function correctly again.
Why it happens: This fault occurs when the water pressure inside your heating system drops below the minimum level required for the boiler to fire up safely. The most common reason is a tiny leak from a radiator valve or joint, though pressure also naturally drops if you have recently bled your radiators to remove air bubbles.
Locate the filling loop (a flexible metal hose) underneath the boiler that connects two pipes.Open the valves at both ends of the filling loop to allow water to enter the system.Watch the pressure gauge on the front of the boiler until it reaches the green zone (typically between 1.0 and 1.5 bar).Close both valves tightly and remove the filling loop if required by your specific model.
Your boiler has stopped working because the water pressure inside the system is too low to operate safely.
Why it happens: This fault occurs when the water pressure inside your heating system drops below a safe operating limit, causing the boiler to shut down to prevent internal overheating. Common reasons include a slow leak from a radiator valve or pipework, or a failure in the expansion vessel which allows the system pressure to escape through the safety discharge pipe.
Locate the filling loop, which is a silver braided flexible hose with one or sometimes two valves underneath the boiler.Open the valve(s) slowly to allow water into the system while watching the pressure gauge on the front panel.Close the valve(s) tightly once the needle reaches the green zone, typically between 1.0 and 1.5 bar.
Your boiler has detected a general internal error and has safely shut itself down to prevent damage, meaning you currently have no heating or hot water.
Why it happens: A solid red light indicates that the boiler's internal safety system has detected a generic malfunction, preventing it from firing up. This is often caused by a failure in the ignition process or a breakdown in communication between the main control board and vital components like the gas valve. While a simple reset may temporarily clear it, the fault usually points to a failing part that is no longer operating within safe limits.
Locate the mode selector switch on the front control panel.Turn the switch to the 'OFF/RESET' position and wait for 5 seconds.Turn the switch back to either the 'Hot Water' or 'Heating and Hot Water' position.
Your boiler has detected a safety issue and has shut down to protect your home, which means you currently have no heating or hot water until it is reset or repaired.
Why it happens: This fault occurs when the boiler fails to light or loses its flame three times in a row, causing it to stop for safety reasons. The most common reasons include a lack of gas supply, a build-up of carbon on the ignition probe, or a component failure that prevents the burner from firing up correctly.
Locate the main control dial on the front of the boiler.Turn the dial to the 'OFF/RESET' position and wait for 5-10 seconds.Turn the dial back to the 'Hot Water' or 'Heating & Hot Water' position to restart the boiler.
Your boiler has lost all power and is completely unresponsive, meaning it is currently unable to provide heating or hot water.
Why it happens: This fault occurs when the boiler's electrical circuit is broken, preventing the control system from turning on. The most common reason is a blown 3A fuse in the wall spur or on the internal board, often triggered by a power surge or a failing internal component causing short circuit.
Check if the main boiler power switch (fused spur) is turned onCheck your home's main consumer unit to see if a circuit breaker has trippedTry replacing the 3-amp fuse in the boiler's external switch
on the Vokera Option
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