For those of you who install Viessmann

The 100

Hey HVHEHCCA,

I think a smaller vitodens should be a 100, because there's a good chance if you're only pushing 10,000-15,000 BTUH's min fire to 40,000-50,000 BTUH's max fire you probably don't need the sophistication of the vitodens 200 controls nor the extra features (chances are you probably won't be heating multiple applications like pool exchangers, or multiple heating temps off of one boiler in most cases). Also consider it'll be for the smaller, average joe house (say rancher sized or 2 smalleish stories) where the person wants Viessmann quality at a reasonable price which is what the Vitodens 100 is supposed to be aimed at if I'm not mistaken. 

As far as combi units, in my opinion to make a combi unit work where it has a half decent chance at hitting all the heating loads without excessive short cycling, but provide ample domestic hot water, you need strong modulation rates. Most boiler manufacturers are handicapped by standards/limits to their modulation rates, yet these tankless manufacturers who don't have the stamps or meet the standards the boiler manufacturers are, can "sneak one in there" with these combi units and "heat boxes." Viessmann as is, isn't known for their high modulation ratios like some of the competition, but it's not in my mind a Viessmann problem neccessarily. As far as I know, with the exception of some of the larger condensing boilers which may have 2 heat exchangers, most residentail condensing boilers are handicapped by a 5 to 1 boiler ratio where a boiler can only modulate down to 20% of it's "normal" fire rate. There are some exceptions - 1 boiler manufacturer argued/questioned what "normal" meant and got away with being allowed to do a 10 to 1 on their 15-150 (15,000 to 150,000). This as I understand is the only boiler that stands a chance at a reasonable chance at a true combi unit because it has the cajones at high fire to put out some domestic hot water and a nice low modulation ratio.

But back to Viessmann - I emailed Viessmann with a question about how to apply their current Vitodens boilers to a house with a 17,000 BTUH heat loss. I was curious how to do this without a buffer tank and eliminate short cycling. The individual who took the time to respond to my question and entertain my idea of larger Delta T's suggested that the only real way to do it was a buffer tank and he explained another system he uses with an indirect, but admittedly he said Viessmann surveys'/watches the market to see what it will bear, so to speak, and that is the point of this thread - to show Viessmann and other manufacturers that there is a market for for smaller mod-cons.

Also, any of you guys actually install the 25000 to 91000 Vitodens 200 combi unit? HOw does it perform?

Rumours?

So what rumours and ETA's have you guys heard as far as what they might be coming out with?