If the unit is fairly new, odds are that it isn't broken, it just needs to have the jumpers moved around (and what ever else the instructions say for the conversion). If the unit has some time on it, I still wouldn't rule out the fact that it needs to be converted, but I suppose a relay could've gone bad as well. But without any name plate info, instructions or schematic, this could prove tricky.
Also, this "previous EC" could have done some tinkering too.
Good luck
