BoilerFaultCodesThe 6 most common faults
Your boiler is struggling because it cannot detect enough water flowing through its internal system, which prevents it from safely heating your home.
Check your boiler's pressure gauge on the front panel; it should be between 1.0 and 1.5 barIf the pressure is below 1.0 bar, locate the filling loop hose underneath the boilerOpen the valves on the filling loop to allow cold mains water in until the needle reaches 1.5 bar, then securely close the valves
Your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.
Locate the external filling loop, which is a silver braided flexible hose connected to two valves under the boiler.Open the valves slowly to allow mains cold water into the system until the pressure gauge on the front panel reads between 1.0 and 1.5 bar.Close both valves tightly to prevent over-pressurisation.
Your boiler has lost its connection to the digital wall thermostat, meaning it no longer knows when to turn the heating on or off.
Switch the boiler off at the fused spur or mains power supply.Wait for 60 seconds to allow the internal electronics to fully reset.Turn the power back on and check if the remote control screen has reconnected to the boiler.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the external filling loop, usually two silver flexible hoses with small taps attached under the boiler.Open the taps slowly to allow water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close both taps tightly and check the boiler display to see if the fault has cleared.
The boiler's control panel detects that one of the buttons is jammed, preventing it from functioning correctly.
Switch off the boiler at the electrical fused spurGently press and release each button on the control panel to see if any feel stuck or fail to 'click'Use a dry, soft cloth or gentle air duster to remove any debris or sticky residue around the buttonsWait 5 minutes and switch the power back on to see if the error clears
Your boiler is failing to light the flame needed to heat your water and home.
Full guide for E01on the Alpha C25 Xtraflame
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