BoilerFaultCodesThe 5 most common faults
01
A02 High Engineer
Your boiler thinks a flame is burning even though it is supposed to be turned off, which causes it to shut down for safety.
Full guide for A0202
F10 High Engineer
Your boiler has stopped working because it is unable to accurately measure the temperature of the water being sent to your radiators or taps.
Full guide for F1003
A15 High Engineer
Your boiler is struggling to clear exhaust gases safely, so it has shut itself down to prevent any risk.
Full guide for A1504
F50 High Engineer
Your boiler's internal computer has detected a serious electronic error and has shut down as a safety precaution.
Full guide for F5005
F51 High Engineer
Your boiler's internal computer has developed an electronic malfunction and can no longer control the heating or hot water safely.
Full guide for F51on the Ferroli i25
Ionisation ElectrodeFlame Sensing CableMain PCBNTC delivery sensorWiring harnessAir pressure switch
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 Ferroli 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
Boiler cover options
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
Approved partner
Get a quote →
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Affiliate links. We may earn a commission at no extra cost to you.