BoilerFaultCodesThe 6 most common faults
Your boiler has shut down completely because a safety sensor has detected that the system is overheating.
Why it happens: This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety switch to prevent damage. The most common reasons are a pump failure that stops water from moving or a blockage in the system causing heat to build up too quickly.
Check that your radiator valves are open and not turned to zero.Verify that the boiler pressure gauge is between 1 and 1.5 bar; top up if necessary.Attempt to reset the boiler by turning the selector switch to the 'OFF/RESET' position and then back to 'ON'.
Your boiler has shut itself down as a safety precaution because it has detected an internal fault or overheating.
Why it happens: This fault occurs when the boiler's internal temperature exceeds safe limits, triggering a shutdown to protect the unit from damage. The most common reasons are a lack of water flow due to a failing pump, a blockage in the heat exchanger, or a faulty sensor sending incorrect temperature readings to the control board.
Locate the reset button or selector switch on the control panelTurn the selector to the 'OFF/RESET' position and wait for 10 secondsTurn the selector back to the 'ON' position and check if the boiler fires up
Your boiler has sensed that the water returning from your radiators is far too hot, causing the system to shut down to prevent damage.
Why it happens: This fault occurs when water is not moving through your heating system fast enough to carry heat away from the boiler, causing it to overheat instantly. The most common reasons are a failed internal pump that isn't pushing the water or a significant blockage within the boiler's heat exchanger. It can also be triggered by a faulty sensor that is incorrectly reporting a high temperature to the control board.
Ensure at least two radiators are fully turned on and not restricted by thermostatic valvesCheck that the internal pump is audible and runningInspect the system pressure gauge and top up to 1.5 bar if it is low
Your boiler has tried to light several times but has failed, likely because gas is not reaching the burner or the spark is not working.
Why it happens: This fault occurs when the boiler's control system fails to detect a flame after five attempts to start. The most common reasons are a lack of gas reaching the unit, a worn-out spark electrode that cannot jump the gap to light the fuel, or a faulty gas valve that isn't opening correctly.
Check that your gas meter has credit and the isolation valve is openCheck if other gas appliances in your home, such as a hob, are working correctlyPress the 'Reset' button on the control panel to attempt a restart
Your boiler has tried to start several times but cannot light the gas to begin heating.
Why it happens: This fault occurs when the boiler's control system attempts to light the burner several times but fails to detect a stable flame. The most common reasons are a lack of gas reaching the unit, worn-out spark electrodes that can no longer create a light, or a dirty sensor that cannot 'see' the flame even if it has ignited.
Check that your gas emergency control valve is in the 'on' positionIf you have a pre-payment meter, check that you have sufficient creditPress the reset button or turn the selector switch to 'OFF/RESET' for 5 seconds and then back to 'ON'
Your boiler's internal computer brain is having trouble processing information and has temporarily stopped working.
Why it happens: This fault occurs when the boiler's main control board experiences a memory failure, preventing it from storing or reading vital operational data. It is typically caused by a hardware malfunction within the circuitry or an electrical surge that has corrupted the board's internal processors.
Locate the power switch or dial on the boiler.Turn the boiler off and wait for 60 seconds.Turn the boiler back on to see if the internal memory resets itself.
on the Vokera Condexa Pro
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
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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