BoilerFaultCodesThe 6 most common faults
01
0E37 High DIY-safe
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
What to try first
Locate the internal filling loop, which is usually a small silver braided hose or a plastic key located underneath the boiler.Open the filling valve slowly to let water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close the valve tightly to stop the flow of water and ensure the boiler resets itself automatically.
02
FE High Engineer
Your boiler is experiencing a communication error between its internal electronic parts, meaning it has stopped working to prevent further damage.
Full guide for FE03
0A1 High Engineer
Your boiler is failing to light the burner, meaning it cannot provide you with any heating or hot water.
Full guide for 0A104
0A2 High Engineer
Your boiler is failing to detect a flame, so it has safely shut down to prevent the release of unburnt gas.
Full guide for 0A205
0A3 High Engineer
Your boiler has switched itself off because it has detected dangerously high temperatures, likely caused by a disruption in the flow of water circulating through your radiators.
Full guide for 0A306
0A5 High Engineer
Your boiler has detected that the internal fan responsible for safely removing exhaust gases is not spinning at the correct speed, causing the system to stop for safety reasons.
Full guide for 0A5on the Alpha Pro Tec 24
Pressure relief valveExpansion vesselFilling loopPrinted Circuit Board (PCB)Wiring harnessControl panel module
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