BoilerFaultCodesThe 6 most common faults
Your boiler has encountered a permanent safety lockout and has stopped working to protect itself.
Why it happens: This fault occurs when the boiler's internal safety sensors detect a critical issue that prevents safe operation, such as the system losing water pressure or the burner failing to light correctly. It acts as a final safety barrier, often triggered by a failing temperature sensor or a hardware component like the fan or ignition system reaching the end of its life.
Check if the water pressure gauge is between 1 and 1.5 barRotate the mode selector switch to 'OFF/RESET' for 5 secondsSwitch the dial back to the previous setting to see if the boiler restarts
Your boiler has likely overheated, causing a safety switch to trip and shut down the system to prevent damage.
Why it happens: This fault occurs when the water inside the boiler exceeds a safe temperature, triggering a mechanical safety switch to cut off the burner. The most common reasons are a failed pump that isn't moving water efficiently, or a build-up of sludge and debris that is restricting flow through the heat exchanger.
Check that your radiator valves are open to allow water to flow.Ensure the system pressure is between 1 and 1.5 bar on the pressure gauge.Wait for the boiler to cool down, then turn the mode selector switch to 'OFF/RESET' for a few seconds before switching it back to 'ON'.
Your boiler has paused because it has detected a temporary issue, likely due to low water pressure or an intake problem, and is waiting for the condition to clear.
Why it happens: This fault occurs when the boiler's safety sensors detect an unstable condition, such as the internal water pressure dropping too low or the air flow being restricted. The system enters a temporary pause to prevent damage, waiting for the correct pressure or air balance to be restored before it attempts to fire up again.
Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.If the pressure is too low, use the filling loop valves to top up the system.Ensure the external flue terminal is not blocked by leaves, debris, or snow.Turn the mode selector switch to 'OFF/RESET' for a few seconds and then back to 'ON'.
Your boiler has entered a test mode and is currently unable to provide normal heating or hot water.
Why it happens: This fault occurs when the boiler has been accidentally switched into 'Combustion Analysis' or 'Service' mode. The most common reason is that the control selector knob was turned too far or left in a specific position meant only for engineers to test the gas levels. While in this state, the boiler ignores your thermostat and hot water taps to run at a fixed output for testing purposes.
Locate the selector dial on the front control panel.Turn the dial to the 'OFF/RESET' position.Wait five seconds, then turn the dial back to your desired 'Heating and Hot Water' setting.
Your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.
Locate the filling loop, which is usually a flexible silver hose with one or two valves underneath the boiler.Slowly open the valve(s) to let mains water into the system until the pressure gauge needle sits between 1.0 and 1.5 bar.Close the valve(s) tightly and check that the boiler restarts.
Your boiler has detected an internal configuration error, likely due to a loose link on the main computer board, which is preventing it from starting up correctly.
Full guide for Check JP1on the Vokera Compact 25
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