BoilerFaultCodesThe 6 most common faults
Your boiler has detected a safety-related issue with its internal components or airflow and has locked itself down to prevent damage.
Why it happens: This fault occurs when the boiler's safety sensors detect that the system cannot safely move air or water through the unit. It is most commonly caused by a mechanical failure in the fan or a blockage in the flue and condensate drainage system that prevents the boiler from 'breathing' correctly. In some cases, it can also be triggered if the unit overheats due to a lack of water circulation.
Check that the system water pressure is between 1 and 1.5 bar on the pressure gaugeTurn the mode selector switch to 'OFF/RESET' for a few seconds, then back to the heater or hot water iconEnsure the external flue terminal is not obstructed by debris or garden growth
Your boiler has stopped working because the water pressure is too low for the system to run safely.
Why it happens: This fault occurs when the internal water pressure drops below the minimum level required for the boiler to operate safely. The most common reasons are a slow leak hidden somewhere in your radiator system or air being released through a safety valve.
Locate the filling loop (the silver flexible hose) underneath or near the boiler.Slowly open the one or two taps/valves on the filling loop until you hear water entering the system.Watch the pressure gauge on the front of the boiler and close the taps once the needle reaches between 1 and 1.5 bar.Restart or reset the boiler by turning the mode selector switch to 'OFF/RESET' and then back to heating/hot water.
Your boiler has detected a general internal error and has locked itself out for safety, meaning your heating and hot water will not work until it is reset or repaired.
Why it happens: This fault occurs when the boiler's internal computer detects an inconsistency in the ignition process or a failure in one of its safety sensors. The most common reasons are that the boiler is struggling to generate a spark to light the gas, or a faulty sensor is sending incorrect temperature readings to the main control board.
Check if your gas prepay meter has creditRotate the mode selector switch to the 'OFF/RESET' position, wait five seconds, then move it back to 'Auto' or 'Hot Water Only'Check your pressure gauge is between 1 and 1.5 bar; if it is too low, top it up using the filling loop
Your boiler has entered a safety lockout mode due to a critical internal fault or an ignition failure.
Why it happens: This fault occurs when the boiler's control system detects a critical safety issue, most often failing to light the flame after several attempts. It can be caused by a lack of gas reaching the burner, a worn-out spark electrode, or an electrical failure within the main control board. Essentially, the boiler has stopped working to prevent unburnt gas from building up or to protect its internal components from damage.
Move the mode selector switch to the 'OFF/RESET' position.Wait approximately 10 seconds.Move the switch back to either 'Hot Water Only' or 'Heating and Hot Water' and wait for the boiler to attempt to reignite.
Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
Why it happens: This fault occurs when the water inside the heat exchanger reaches an unsafe temperature, triggering a safety sensor to cut the power. The most common reasons are a failed pump that isn't moving water around the system or a blockage of sludge and debris restricting the flow. Sometimes, a faulty sensor can also trick the boiler into thinking it is overheating when it actually isn't.
Wait at least 20 minutes for the boiler to cool down naturally.Ensure all radiator valves (TRVs) are fully open to allow water to flow.Turn the mode selector switch to the 'OFF/RESET' position, wait a few seconds, then turn it back to the original setting.
Your boiler has likely overheated or has an issue with its internal fan system, causing it to shut down for safety.
Why it happens: This fault occurs when the boiler's internal components detect that the unit is either getting too hot or that the fan isn't safely clearing waste gases. The most common reasons are a blockage in the flue, a failing circulation pump, or a simple mechanical failure of the safety sensors themselves.
Turn the mode selector switch to 'OFF/RESET' for a few seconds.Move the switch back to either 'Hot Water' or 'Heating and Hot Water' mode.Check that all radiator valves are open and your wireless thermostat has working batteries.
on the Vokera Compact HE
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