BoilerFaultCodesThe 6 most common faults
01
S 01 High DIY-safe
Your boiler failed to light on its first try and needs a quick reset to attempt to restart the burner.
What to try first
Locate the reset button on your boiler control panel.Press and hold the reset button for 2-3 seconds.Wait up to 60 seconds to see if the boiler ignition cycles successfully.
02
A17 High Engineer
Your boiler has detected that water is not moving through the system correctly, which is preventing it from heating your home or water safely.
Full guide for A1703
A18 High Engineer
Your boiler has detected that water is not moving through the system properly, which is causing it to shut down to prevent overheating.
Full guide for A1804
A33 High Engineer
Your boiler's air extraction system is not working correctly, which prevents the unit from starting safely.
Full guide for A3305
A97 High Engineer
Your boiler has detected a software or internal communication error with its main brain, meaning it has safely shut down to prevent incorrect operation.
Full guide for A9706
E 99 High Engineer
Your boiler has detected a series of internal faults and has locked itself down for safety reasons after multiple failed attempts to function.
Full guide for E 99on the Ariston Genus One 30
Ignition electrodeGas valveIonisation probeCirculation pumpFlow sensorSystem filter
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
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