BoilerFaultCodesThe 6 most common faults
01
RY2 High Engineer
Your boiler has stopped working because the connection to the control system is failing to receive the necessary electrical power.
Full guide for RY202
RY4 High Engineer
Your boiler is failing to start because it cannot confirm that the internal fan is operating correctly, preventing the safe clearing of exhaust gases.
Full guide for RY403
LED 4 (A) High Engineer
Your boiler has stopped providing hot water because it is struggling to read or regulate the temperature from its water heating sensor.
Full guide for LED 4 (A)04
LED 5 (A) High Engineer
Your boiler's electronic brain is malfunctioning and cannot correctly process its startup sequence, meaning it will currently fail to provide heating or hot water.
Full guide for LED 5 (A)05
LED 6 (A) High Engineer
Your boiler has stopped working because it is unable to accurately detect the water pressure or temperature, preventing it from safely heating your home or water.
Full guide for LED 6 (A)06
LED 4 (B) High Engineer
Your boiler has stopped working because it cannot properly read the water temperature or it has detected that it is running too hot.
Full guide for LED 4 (B)on the Ferroli Hawk II
PCBWiring harnessAir pressure switchFan assemblyDHW NTC thermistor sensorWiring loom
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