i was told by a reputable HVAC contractor that while a good product, Viessman offers no support or parts availability.
He thought Buderus was much better in those two categories PLUS was a superior product in terms of design.
As I have no way to refute his comments (or know if i should even try), i would appreciate any knowledgeable insights.
I install Buderus all the time. They really are great units. As far as Viessman goes, I carry no parts for one on my truck. Buderus on the other hand is very service friendly.
Buderus is nice and has support, I think Viessmann is like a Rolls Royce,big bucks and not alot around for people to stock parts.
Never heard of problems getting parts for either.
Both fill a niche, and only compete in one small area of there applications, IMO.
Put in what the house needs, not hat YOU want.