Owner of this Ariston E Combi 24 described the fault as follows:
When I got to site I noticed that boiler would take 2-3 attempts at ignitions with 2nd or 3rd one being successful and boiler would not go into lockout while I was on site. After testing rectification, gas pressures and combustion I got satisfactory results for all of those. I suspected problem with either gas meter regulator or one of the main components of the boiler not connected to rectification or ignition. Gas meter supply and governor checks confirmed that in fact the problem was on the boiler side. While testing all of the above I managed to witness boiler going into lock out.
This early Ariston E Combi does not have a digital display and error codes are communicated through number of combinations of led temperature display. Below is a picture of Flame Lift / Ignition lock out error code with 3 temperature led illuminated together with red ignition error led illuminated below on the right hand side.
Close up of the error code below
Since gas supply has been operating correctly, combustion and rectification was giving correct results that left only one major component that could have been faulty. Faulty part got replaced at next visit and boiler is now working correctly.
Boiler igniting correctly and displaying actual operating temperature instead of an error code below.
I also noticed pressure going up to around 3bar while system was heating up pointing to flat expansion vessel. Client is supposed to book a second service visit to rectify this problem.