PSG Caddy PF01010 - 7 Part F - Ducts and Dampers Dimensions; Ducts and Dampers Dimensions (Examples of Calculation)

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7 PART F - DUCTS AND DAMPERS DIMENSIONS
7.1 DUCTS AND DAMPERS DIMENSIONS (EXAMPLES OF CALCULATION)
SIMPLIFIED METHOD
DISTRIBUTION SYSTEM
Ducts size (heat)
4 inch outlet reduce by 1”
5 inch outlet reduce by 2”
6 inch outlet reduce by 3”
Always by 8” thick
N.B.: The main duct must be reduced every
2 outlets.
Ducts specifications (heat)
Dimensions Length Elbow Average
equivalence
4” 10’ 1 x 90
o
Max 4,000 Btu
5” 10’ 1 x 90
o
Max 6,000 Btu
6” 10’ 1 x 90
o
Max 7,000 Btu
DAMPER
For a 4” warm air outlet: 2” x 10” damper
For a 5” warm air outlet: 2” x 12” damper
or 4” x 10”
For a 6” warm air outlet: 2” x 14” damper
or 4” x 12””
WARM AIR SYSTEM INSTALLATION
HOUSE DIMENSIONS
Example: 28 x 40 bungalow = 1,120 sq. ft.
28 x 40 x 8 = 8,960 sq. ft.
x 1.8 Ch. air/hr: 16,128 Btu
Exposed walls :
40 + 40 + 28 + 28 = 136
x 8 = 1,088 sq. ft. x 22 = 23,936 Btu
Number of windows :
12 of 3 x 4 = 144 x 60 = 8,640 Btu
Number of doors :
2 x 3’ x 7’ = 42 x 100 = 4,200 Btu
52,904 Btu
Non-insulated basement: 25 %
Insulated basement: 15 % 7,906 Btu
Or 54 Btu per sq. ft. 60,840 Btu
FOR ELECTRIC ELEMENTS 80% =
48,672 Btu or 14,28 kW
TO BE ADDED: House 1 1/2 floor = 25 %
House 2 floors = 40 %
BEDROOM (for example: 12 x 12)
12 x 12 x 8 = 1,152 sq. ft.
x 1.8 Ch. air/h = 2,074 Btu
Exposed walls:
12 + 12 x 8 : 192 x 22 = 4,224 Btu
Windows:
3 x 4 x 60 = 720 Btu
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