When I used to help install furnaces. If we would put
in a PVC vent furnace, often we'd have to put in a
chimney liner for the water heater. Boss would
explain to me that there wasn't enough heat to keep
the chimney warm. The flue liner would be expanding
aluminum tube that went to the top of the chimney.
I'm not sure what the formula for that is.

..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On 9/9/2013 3:01 AM, nestork wrote:

Often two appliances drafting up the same chimney at the same time will
work better than only a single appliance because the increased amount of
flue gas warms the chimney up more, and the result is better drafting
from natural convection.