an enquiring mind

Joe_55

an enquiring mind would like to know if Viessmann Vitodens is the only mod/con boiler that varies the GPM through its HX. this appears to be the only way to optomize condensing by keeping flow in the primary (boiler) equal to or less than flow in the secondary (emitters) preventing recirculation of water that has not passed through the emitters.

some other boilers require a minimum of 8 gpm to function properly, Is there any way to have 8 gpm in an emitter loop without bypassing. thanks for your thoughts .Bill.

S Ebels

Yep

The Vitodens is the only one I have heard of with a smart circ built-in. It's only on the two small sizes (6-24 & 8-32, the larger ones use a field installed circ. This is due to the fact that the larger boilers are usually hooked up to loads that require a fair amount of flow on the system side and the boiler flow can be constant, allowing the burner alone to seek the right level/temp.

My gut feeling is that large required flows through a M/C boiler, in proportion to actual output, are dictated by the construction of the HX more than anything else. Some are fairly light gauge material and it doesn't take long to fry 'em if things aren't right.

Jamie_6

Hey Bill!

I know nothing about Viessmann's (not luckey enough to install one yet)

But did want to say Happy Holidays!

Jamie