Installation Guide
www.usaprocom.com
200199-01B8
Outlet
Air
Ventilated
Attic 
Outlet
Air
Inlet
Air
Inlet Air
Ventilated 
Crawl Space
To 
Crawl
Space
To Attic
Or
Remove
Door into
Adjoining
Room,
Option
3
Ventilation Grills 
Into Adjoining Room,
Option 2
Ventilation
Grills Into
Adjoining 
Room,
Option 1
12"
12"
Ventilation Air From Outdoors
AIR FOR COMBUSTION AND VENTILATION
Figure 3 - Ventilation Air from Outdoors
Provide  extra  fresh  air  by  using  ventilation 
grills or ducts. You must provide two perma-
nent openings: one  within 12" of the  ceiling 
and one within 12" of the oor. Connect these 
items directly to the outdoors or spaces open 
to the outdoors. These spaces include attics 
and crawl spaces. Follow the National Fuel 
Gas Code, ANSI Z223.1/NFPA 54, Air for 
Combustion and Ventilation for required size 
of ventilation grills or ducts.
IMPORTANT:  Do  not  provide  openings 
for  inlet  or  outlet  air  into  attic  if  attic  has  a 
thermostat-controlled power vent. Heated air 
entering the attic will activate the power vent. 
Rework worksheet, adding the space of the 
adjoining  unconned  space.  The  combined 
spaces must have enough fresh air to supply 
all appliances in both spaces.
Figure 2 - Ventilation Air from Inside 
Building
VENTILATION AIR
Ventilation Air From Inside Building
This fresh air would come from an adjoining 
unconned  space.  When  ventilating  to  an 
adjoining unconned space, you must provide 
two permanent openings: one within 12" of the 
ceiling and one within 12" of the oor on the 
wall connecting the two spaces (see options 
1 and 2, Figure 2). You can also remove door 
into adjoining room (see option 3, Figure 2). 
Follow  the  National Fuel Gas Code, ANSI 
Z223.1/NFPA 54, Air for Combustion and 
Ventilation  for  required  size  of  ventilation 
grills or ducts.










