CleaverBrooks CFC - Page 61

Chapter 3 — Stack and Intake Vent Sizing and Installation
Part No. 750-263 3-13
2. Stack design using direct vent combustion
6" Standard 4" 6" 75 75
4" Option 4" 4" 40 40
CFC750 6" Standard 4" 6" 40 40
8" Standard 6" 8" 60 60
6" Option 6" 6" 40 40
10" Option 6" 10" 70 70
10" Standard 6" 10" 40 40
8" Option 6" 8" 30 30
12" Option 6" 12" 45 45
12" Standard 6" 12" 30 30
10" Option 6" 10" 25 25
CFC 2500 12" Standard 8" 12" 100 100
* Each additional 90 elbow equals 5 equivalent feet of ductwork. Subtract from the maximum or
minimum length accordingly.
** Increasing the diameter of the air intake will reduce the pressure drop and thereby allow longer total
vent lengths.
CFC1500
CFC1800
Maximum allowable pressure drop in combustion air intake duct is - 0.25" w.c.
Boiler
CFC 500
CFC1000
Maximum length of
Flue Gas Vent in
Feet*
Maximum length of
Air Intake Duct in
Feet**
Boiler Stack
Connection
Boiler Air
Intake Duct &
Connection
Boiler
Vent/Stack
Size