On Thu, 24 Jan 2013 10:31:00 -0800 (PST), "
wrote:




But too much is no good either. *You need balance and there are curves on
the optimum residence time needed for heat transfer to take * place. *Very
slow air movement gains a bit temperature change, but at the expense of
proper circulation.

Slow air movement results in LESS heat transfer because
the air leaving is at a higher temperature and less heat is
extracted from the combustion gases. The more airflow,
the more heat that will be extracted, the more heat you
will get out for the same energy put in. But it's a diminishing
return, moving more air doesn't come for
free, and there are other considerations.


Unless we put numbers on this, it is all meaningless. How slow is
slow? How much heat potential can be absorbed, etc, etc. Absorbing
the maximum heat is also useless unless you have the air flow to
properly distribute it where needed.

The manufacturer spent tons of money engineering these things so their
settings are a damned good starting point.