BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside your heating system has dropped too low.
Locate the external filling loop, which is usually a flexible silver hose under the boiler connecting two pipes.Open the valves on both ends of the filling loop to let mains water into the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone, typically between 1.0 and 1.5 bar.Close both valves tightly immediately and ensure the pressure gauge stays stable.
Your boiler's control panel detects that one of the buttons is jammed or sticking, preventing it from functioning correctly.
Switch off the boiler at the electrical fused spur.Carefully inspect the buttons on the control panel to see if one is physically stuck or depressed.Gently press the surrounding area of the buttons to release any debris or dirt and reset the stuck switch.
Your boiler has lost its wireless connection to the temperature controller, meaning it doesn't know when to turn your heating on or off.
Replace the batteries in your wireless room thermostat unit.Check if the receiver unit connected to the boiler has power and is not showing a fault light.Attempt to re-pair the thermostat and the boiler receiver by following the pairing instructions in your Alpha user manual.
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 usually a flexible silver hose connected to two valves under the boiler.Gradually open the valves to let water into the system while watching the pressure gauge on the front of the boiler.Close the valves firmly once the needle sits between 1.0 and 1.5 bar, then restart the boiler.
Your boiler is trying to start up but cannot successfully light the internal flame to produce heat.
Full guide for 01Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
Full guide for 02on the Alpha Intec 40GS2
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