BoilerFaultCodesThe 6 most common faults
Your boiler has tried to light several times but cannot detect a flame, causing the system to lock out for safety.
Check that your gas emergency control valve is in the 'on' positionIf you have a prepay meter, ensure you have sufficient creditAttempt to reset the boiler by turning the selector switch to the 'R' position for five secondsCheck if other gas appliances, like a hob, are working to confirm gas supply
Your boiler has switched itself off because it has become too hot inside, likely due to a circulation problem or a temporary blockage.
Check that all radiator valves are fully openEnsure your system water pressure is between 1.0 and 1.5 bar on the gaugePress and hold the 'Reset' button for a few seconds to restart the boiler
Your boiler has been manually reset too many times in a short period and has locked itself for safety reasons.
Turn off the electrical power supply to the boiler at the fused spur switchWait for at least 30 secondsTurn the power back on to clear the software lockout and allow a new reset attempt
Your boiler has detected that the water pressure in the central heating system is too low to operate safely.
Locate the filling loop (braided silver hose) underneath or near the boilerSlowly open the tap or taps on the filling loop until you hear water movingWatch the pressure gauge and close the taps once the needle reaches between 1 and 1.5 bar
Your boiler has shut down because the exhaust gases have become too hot, which is a safety measure to prevent damage to the system.
Full guide for 03Your boiler has detected an electrical problem with the component that controls the gas flow, causing the system to shut down for safety.
Full guide for 04on the Alpha E-Tec NXS
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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