|Wind Loading on a multi-story building is another
common cause of smoke and backpuffing. As the wind flows against the
second story vertical wall, a high pressure zone develops at the chimney
top. Although a Vacu-Stack is not guaranteed as solution to this
problem, field reports show satisfactory results in more than 50 percent
of the installations.
The occurrence of smoke and backpuffing when air is calm may be
caused by a number of structural factors that relate to the heating
system. The chimney may be too short or the flue opening may be too
large or small for the heating appliances. Smoke may also occur if the
chimney is blocked with soot, creosote or debris.
In a relatively air-tight house, negative pressure problems can be
caused by appliances that exhaust the inside air, such as cooking
ranges, exhaust fans, a clothes dryer vent, furnaces or other devices.
Your individual chimney problem may be the result of a variety of