Do I Have To Intake Air From *

[boilerventing]

I'm replacing my boiler for a Viessmann Vitodens 100-W (Category IV). I'd like your help deciding whether to take fresh air from inside or outside my house.

If it gets air intake from the surrounding room instead of outside, would there be any concern of CO backdrafting into my *

Does it become a Natural Draft (Category I) boiler if I use air from the surrounding * Or is it Category IV regardless of *

[Trini2dbone]

boilerventing -
> I'm replacing my boiler for a Viessmann Vitodens 100-W (Category IV). I'd
> like your help deciding whether to take fresh air from inside or outside my
> house.
>
> If it gets air intake from the surrounding room instead of outside, would
> there be any concern of CO backdrafting into my *
>
> Does it become a Natural Draft (Category I) boiler if I use air from the
> surrounding * Or is it Category IV regardless of *

I am not farmiliar with this particular boiler. However with any fossil fuel combustion unit it is always better to take air from outside as this is where the by-products (fumes) are being exhausted. Take combustion air air from outside and dump it's fumes outside * no internal change in building pressure. If you take combustion air from inside then dump it outside you will eventually have a building with negative pressure - not good.