Owner manual

12
Fresh Air Duct Capacities For Ducts Supplying Fresh Air To Boiler In Tightly Constructed Houses
Table 3 - FRESH AIR DUCT CAPACITIES
THROUGH LOUVERS
Fresh Air
Duct Size
¼” Mesh
Screen
Wood
Louvers
Metal
Louvers
(Btuh)* (Btuh)* (Btuh)*
3 ½” x 12” 144,000 36,000 108,000
8” x 8” 256,000 64,000 192,000
8” x 12” 384,000 96,000 288,000
8” x 16” 512,000 128,000 384,000
*Btuh = British Thermal Units per hour based on
opening covered by ¼” mesh screen , wood lou-
vers, or metal louvers.
Figure 4 - Fresh Air Openings
7 - FRESH AIR FOR COMBUSTION