The answer as to why is that the HVAC industry does NOT want DIY installations. Such stuff will hurt their bottom line don't you know!!!
That is also why the companies usually will not honor a warranty unless you get a licensed HVAC to install the unit (they exist to srve the HVAC industry...
I bought the same unit for installation in a converted screen porch (not yet installed),
My concern is the warranty if the support you received was that bad. What do you think about the warranty for down the road?
thanks