Product Manual

HeatPack Furnace Installation and Operation Manual
26
The total area of secondary duct outlets must be equal or slightly less than the total area of
the outlets used on the hot air distribution plenum (B).
Example of surface calculation according to the number of outlets used in the
plenum:
Diameter of plenum
outlet (in)
Surface of plenum
outlet (in
2
)
Number of outlets on
the plenum
Total surface of
plenum outlets used
(in
2
)
6
28
6
170
The acceptable total area of secondary outlets would therefore be:
Diameter of
secondary outlet (in)
Surface of
secondary outlet
(in
2
)
Number of
secondary outlets
Total surface of
secondary outlets
used (in
2
)
4
12 ½
9
112 ½
5
19 ½
1
19 ½
6
28
1
28
The total area of the secondary outlets of this system would be
acceptable because it is equal to or slightly less than the total
area of the plenum outlets.
160
B