While you wait for answers, we may have found some information which could help you.
Click here for Ariston 23mffi BoilerAriston Microgenus 23 MFFI PCB Defect?
error code e02 wont work when pressurised?
gas boiler keeps going to reset?
What is the problem?
Why does my boiler remain ON - even when switch is moved to OFF?
No display on Ariston e-combi approx3yrs old?