They won't give any fault codes, but to put it into installer mode, turn the HW and CH knobs to zero, then turn and hold the selector knob to reset/ restart for about 3-5 seconds and that will be in installer mode and will give you the fault/s.
I only work on the older ones now, don't touch the newer versions and haven't fitted an Alpha for about 4 years,
Have replaced about 200 with different makes in the last 4 years!
Well, that's me re qualified for another 5 years, can go back to work now and rest the ole brain!! Lol, used Gas Train at Medway, and will recomend those guys!