BoilerFaultCodesThe 6 most common faults
Your boiler is failing to light the gas, which means your heating and hot water will not work until the system is reset or repaired.
Why it happens: This fault occurs when the boiler's control system tries to start the burner but cannot detect a flame after several attempts. The most common reason is a lack of gas reaching the burner or a failure in the ignition system that prevents the spark from creating a steady fire. It can also be caused by worn-out sensors that fail to tell the boiler that a flame is actually present.
Check if other gas appliances, like a hob, are working to ensure gas is being supplied to the property.Ensure your gas meter has credit if you use a prepay meter.Press the 'Reset' button on the boiler control panel once to see if the system restarts.
Your boiler has shut down completely because its internal computer has lost power or suffered a serious electrical fault.
Why it happens: This fault occurs when the boiler's main control board loses its electrical connection or suffers a complete internal failure. It is often caused by a blown fuse, loose wiring, or a power surge that has damaged the electronic components. Without a stable power signal, the boiler's computer cannot manage the safety checks and must shut down for security.
Check if your home has had a power cut or if a fuse has tripped in your consumer unitEnsure the boiler's fused spur switch (usually nearby) is turned onPress the Reset button or turn the control knob to 'OFF/RESET' for 10 seconds, then back to the heater icon
Your boiler has sensed that the water inside is Getting too hot and has shut down to prevent damage.
Why it happens: This fault occurs when the water leaving the boiler reaches an unsafe temperature because it isn't moving through the system fast enough. The most common reasons are a failing pump that can't push the water round, or a build-up of debris and sludge that has partially blocked the internal pipework.
Check all radiator valves are fully open to allow water flowEnsure the boiler pressure gauge is between 1.0 and 1.5 barRestart the boiler using the reset dial or button
Your boiler has detected that the water returning from your radiators is getting too hot, indicating a possible circulation or sensor issue.
Why it happens: This fault occurs when the boiler detects that the water returning from your radiators is nearly as hot as the water leaving the unit, meaning heat isn't being transferred into your rooms. The most common reasons are a blockage in the system, a failing pump that isn't moving the water fast enough, or a faulty sensor providing an incorrect temperature reading.
Check that all radiator valves (TRVs) are fully openEnsure the boiler pressure is between 1.0 and 1.5 barRestart the boiler using the reset dial
Your boiler is overheating because water isn't moving through the system quickly enough to carry the heat away.
Why it happens: This fault occurs when the boiler's internal temperature rises too rapidly, triggering a safety shutdown to prevent damage. The most common reason is a blockage or restriction in the system pipes, or a faulty pump that is failing to circulate hot water away from the burner quickly enough.
Check that at least two or three radiators have their valves turned fully openEnsure the external heating pump (if visible) is runningReset the boiler once the system has cooled down
Your boiler has sensed that the water is heating up too quickly or unevenly, causing it to shut down for safety.
Why it happens: This fault occurs when the internal sensors detect that water isn't flowing away from the heat exchanger quickly enough, causing a rapid heat buildup. The most common reason is a failing circulation pump or a blockage in the system caused by a buildup of sludge and debris. It can also be triggered by air trapped within the boiler or a sensor that has become faulty and is giving incorrect readings.
Check that your system water pressure is between 1 and 1.5 bar on the pressure gauge.Ensure all radiator valves and the boiler service valves are fully open.Gently bleed your radiators to remove any trapped air that might be blocking circulation.Press the reset button to see if the boiler restarts once it has cooled down.
on the Vokera Pinnacle
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