Now, I'm no EE and not even an electrician but it is my understanding that on a three phase with 208V between phases, one still gets 120V to a fourth neutral. Is there any "normal" system that would give you much less, like 104V?
My furnace guy was making excuses for being a day late. He said he wasted the day before on a three phase system where the voltage was low. He said he didn't realize that a three phase 208Y would put out just 104V when split. I've never heard of such a thing. I dunno... sounds like something was jury rigged.