BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water level inside the system has dropped too low to operate safely.
Why it happens: This fault occurs when the sealed water circuit loses its required pressure, usually due to a small leak in the pipework or at a radiator valve. It can also happen if the expansion vessel has lost its internal air charge, causing water to be forced out of the safety discharge pipe.
Locate the filling loop, which is usually a flexible silver hose with one or two small valves underneath the boiler.Slowly open the valve(s) to allow cold water into the system, watching the pressure gauge rise.Close the valves tightly once the pressure gauge reaches between 1.0 and 1.5 BAR.
Your boiler is unable to light the gas to start the heating process, causing the system to lock out for safety.
Why it happens: This fault occurs when the boiler attempts to start up but cannot successfully establish a flame to heat the water. The most common reasons include a lack of gas supply to the unit, a worn-out spark electrode that can no longer create a light, or a faulty gas valve that isn't opening correctly.
Check if your gas supply is active by testing another gas appliance like a hob.Ensure the gas stopcock valve is fully open.Press and hold the reset button for a few seconds to attempt a restart.
Your boiler has switched itself off as a safety precaution because it has either failed to light or has become too hot.
Why it happens: This fault occurs when the boiler's internal sensors detect that the water temperature has exceeded a safe limit or the flame failed to light after several attempts. Often, this is caused by a lack of water flow through the heat exchanger, perhaps due to a failing pump or an airlock, triggering the safety shut-off to prevent internal damage. It can also be caused by a build-up of debris or a fault with the ignition system preventing a stable flame.
Locate the mode selector switch on the front control panel.Turn the switch to the 'RESET' position and hold it for a few seconds.Turn the switch back to the original 'Heating' or 'Hot Water' position and wait for the boiler to restart.
Your boiler has switched itself off as a safety precaution because it either failed to light properly or got too hot.
Why it happens: This fault occurs when the boiler's internal sensors detect that the burners failed to light after several attempts or that the internal temperature has become dangerously high. The most common reasons include a lack of gas reaching the burner, a worn-out ignition spark, or a blockage that is preventing water from circulating properly through the heat exchanger.
Locate the mode selector switch on the front control panel.Turn the switch to the 'RESET' position and hold it for a few seconds.Return the switch to the 'ON' position and wait for the boiler to attempt to restart.
Your boiler has detected that the water pressure is too low to operate safely and has switched itself off to prevent damage.
Why it happens: This fault occurs when the water volume inside your central heating system drops below a safe operating level, often due to a small leak in the pipework or a radiator. It can also happen if your radiators were recently bled without the system being topped up, or if an internal component like the expansion vessel is no longer holding pressure correctly. When the pressure drops too low, the boiler shuts down to prevent the internal heat exchanger from overheating and sustaining permanent damage.
Locate the external filling loop (the flexible silver hose) under or near the boiler.Slowly open the one or two taps on the hose until you hear water entering.Watch the pressure gauge and close the taps once the needle reaches between 1 and 1.5 bar.
Your boiler has safety-locked itself to stop the flow of gas, likely because it failed to light or lost its flame.
Why it happens: This fault occurs when the boiler tries to ignite but fails to establish or maintain a stable flame, prompting the system to shut off the gas for safety. The most common reasons include a worn-out ignition spark, a blockage in the gas supply, or an issue with the internal sensors that detect the flame.
Locate the mode selector switch on the front panel.Turn the switch to the 'RESET' position and hold it for a few seconds.Return the switch to your desired mode (heating or hot water) and wait for the boiler to restart.
on the Vokera Mynute 23E
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