Could just be that it's not level enough - some fridges are very fussy about being level for the EHU.
Mine recently went into 'defrost mode'. The hot weather had made it ice up and it switched itself off... I switched it off at the plug socket, and left overnight. The next day I plugged it in - nothing for an hour, although it was putting out heat through the vent. Then I read in the manual that the first time used (or after defrosting) it needed to be turned on for 3 hours or more.
So we went out for the day. When we got back, it had started working again.
Check that there is heat coming out of the vent whilst on EHU - if there is, just leave it for a good while. Worked for me.
if EHU is sound there is a chance the element has failed.the green light would still light up.run it on gas for 8 hours to rid of any condensation then try again.also check your 240 volt trip box has not tripped off.if on site it could be the outside post has tripped off.
------------- the only silly question is the one you do not ask.