BoilerFaultCodesThe 6 most common faults
The boiler is trying to start up but cannot light the gas or confirm that a flame has stayed lit.
Check if your gas meter has credit and the isolation valve is openCheck if other gas appliances, like a hob, are working correctlyPress the 'Reset' button on the front of the boiler
Your boiler has become too hot and has switched itself off as a safety precaution to prevent damage.
Check that your radiator valves are open and not turned to off or zero.Wait 30 minutes for the system to cool down completely.Press and hold the 'R' (Reset) button for a few seconds to restart the boiler.
Your boiler has detected that the water pressure in the system is too low for it to operate safely.
Locate the filling loop (usually two blue levers or a braided hose underneath the boiler)Slowly open the valves until you hear water entering the systemMonitor the pressure gauge and close the valves once the needle reaches 1.5 bar
Your boiler has lost its wireless connection to your room thermostat, meaning it doesn't know when to turn your heating on or off.
Check the batteries in your room thermostat and replace them with fresh high-quality batteries.Power cycle the boiler by switching it off at the fused spur for 60 seconds and turning it back on.Attempt to re-pair the thermostat to the receiver unit following the manufacturer's user manual instructions.
Your boiler is struggling to circulate water properly, likely because there is trapped air in the system or a blockage preventing the water from flowing as it should.
Check your boiler's pressure gauge and ensure it is between 1 and 1.5 bar.Bleed all radiators in your home starting from the lowest level up to the highest to release trapped air.Top up the system pressure to 1.5 bar using the filling loop if required, then restart the boiler.
Your boiler has detected that the exhaust gases are becoming too hot and has shut down as a safety precaution to prevent internal damage.
Full guide for 03on the Alpha Evoke NX
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 Alpha 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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