BoilerFaultCodesThe 6 most common faults
Your boiler has failed to light because it is not detecting a flame, which means your heating and hot water have temporarily stopped working.
Check that your gas supply is turned on and other gas appliances in the house are working.Check if your gas prepayment meter has run out of credit if applicable.Locate the boiler's reset button, hold it down for about 5 seconds, and release to see if the boiler reignites.
Your boiler has shut down because it has gotten too hot, likely due to low water pressure in the system.
Check your boiler's pressure gauge to ensure it is between 1 and 1.5 bars.Use the filling loop to top up the water pressure if it is too low.Press the reset button on your boiler once the pressure is corrected.
Your boiler has stopped working because the water pressure inside the system has dropped too low.
Locate the filling loop valves underneath your boiler.Open the valves slowly to allow water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valves tightly and press the reset button on your boiler.
Your boiler has detected an issue with the internal fan that safely removes combustion gases, so it has locked out to prevent unsafe operation.
Full guide for A03Your boiler has temporarily stopped working because it is getting incorrect temperature readings from its internal sensors, meaning it cannot safely regulate the heat.
Full guide for A07Your boiler has temporarily stopped working because it cannot accurately read the temperature of the water returning from your radiators.
Full guide for A08on the Vokera Unica
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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