BoilerFaultCodesThe 6 most common faults
01
31 High Engineer
Your boiler has stopped working because it cannot light its internal flame to heat your water.
Full guide for 3102
A17 High Engineer
Your boiler has detected that water is not flowing through the system correctly, which is preventing it from heating your home safely.
Full guide for A1703
A18 High Engineer
Your boiler has detected that hot water isn't moving around your radiators or pipes properly, causing it to shut down to prevent damage from overheating.
Full guide for A1804
A33 High Engineer
Your boiler has detected that the internal fan responsible for safely removing exhaust gases is not spinning correctly, so it has shut itself down to keep your home safe.
Full guide for A3305
A97 High Engineer
The internal computer in your boiler is experiencing a communication error or software glitch, preventing it from managing your heating and hot water correctly.
Full guide for A9706
E 99 High Engineer
Your boiler has failed to start multiple times and has automatically locked itself for safety to prevent a gas buildup.
Full guide for E 99on the Ariston Genus 30 Plus
Ignition electrodeGas valveFlame rectification probeCirculation pumpSystem filterFlow sensor
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 Ariston 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