Instructions / Assembly
Installing Your Heater 
AIR REQUIREMENTS 
The requirements for providing air for combustion and ventilation 
are listed in the National Fuel Gas Code NFPA 54/ANSI Z223.1 (in 
Canada:  CAN/CGA  B149).  Most  homes  will  require  that  outside 
air be supplied to the heated area by means of ventilation grilles 
or ducts connecting directly to the outside or spaces open to the 
outdoors such as attic or crawl space. The only exception is when 
the  furnace  area  meets  the  requirements  and  definitions  for  an 
unconfined space with adequate air infiltration. 
WARNING:  Danger  of  property  damage,  bodily 
injury or loss of life. The furnace and any other fuel- 
burning appliances must be provided  with enough 
fresh  air  for  proper  combustion  and  ventilation  of 
flue gases. Most homes will require that outside air 
be supplied into the heated area. 
All  air  openings  and  connecting  ducts  must  comply  with  the 
following: 
If the furnace is installed in an area with another gas appliance(s), 
the  total input rating  of all  appliances must  be considered when 
determining  the  free  area  requirements  for  combustion  and 
ventilation air openings.  
Ducts must have the same cross-sectional area as the free area 
of the openings to which they connect.  The minimum dimension 
of rectangular air ducts must not be less than 3-inches in length or 
height. 
LOUVERS / GRILLES AND SCREENS COVERING  
FREE AREA OPENINGS 
If a screen is used to cover the opening(s), it must not be smaller 
than  1/4-inch  mesh.    Use  the  free  area  of  a  louver  or  grille  to 
determine  the  size opening required to  provide the  free  area 
specified.  If the free area is not known, assume a 20% free area 
for wood and a 60% free area for metal louvers or grilles. 
EXAMPLE 1 
FURNACE LOCATED IN UNCONFINED SPACE.
*
*
An unconfined space must have a volume of a minimum 50 cubic 
feet  per 1000 Btu/hr. of  total of  all appliances in area. Adjoining 
rooms  may  be  included  only  if  there  are  no  doors  between  the 
rooms, or if special provisions are made such as ventilation grilles 
installed between connecting rooms. 
Page 10, figure 8 shows the minimum area in square feet' based 
on 8 foot ceiling heights, required for different Btu/hr. input ratings. 
A.  If your furnace is in  an open area  (unconfined space*) the 
air that leaks through the cracks around doors and windows 
may be enough for combustion and ventilation air. The doors 
should not fit tight. The cracks around windows should not 
be caulked or weather stripped. 
  To determine if infiltration air is adequate, perform following 
checks: 
1.  Close  all  doors  and  windows.  If  you have a  fireplace, 
start a fire and wait until flames are burning vigorously. 
2.  Turn on all exhausting devices, such as: 
 kitchen  and  bathroom  exhaust  fans 
 dryers (gas and electric) 
3.  Turn  on  all  vented  gas  appliances,  such  as: 
 heating  equipment  (includes  any  room  heaters) 
 water heater 
4.  Wait ten (10) minutes for drafts to stabilize. 
5.  Check for draft hood spillage at each appliance. (Hold a 
lighted match 2 inches from draft opening. See Fig. 6.) 
B.  No Spillage 
If  the  match  flame  pulls  toward  draft  hood  -  this  indicates 
sufficient infiltration air: 
1.  Return  exhausting  devices  and  appliances  to  the 
condition you found them. 
C.  Draft Hood Spills 
If there is spillage at a draft hood (match goes out or flame 
wavers away from draft hood): 
1.  Check for plugged flue connectors and chimneys. Check 
and repair, stoppage and test again. 
2.  If you have a fireplace, open a window or door near the 
fireplace and then check for spillage. 
a)  If spillage stops, do not use the fireplace without a 
nearby  window  or  door  open  until  you  can  supply 
fresh air by a permanent duct. 
3.  If you have  kitchen and  bathroom exhaust fans,  turn 
them off and check for spillage. 
a)  If  spillage stops, do not use exhaust fans  until you 
can supply fresh air by a permanent duct. 
WARNING:  Danger  of  property  damage,  bodily 
injury  or  loss  of  life.  Draft  hood  spillage,  with 
unobstructed  vents,  indicates  that  additional  air 
must be  brought into the structure  from outside. 
Keep a window open (minimum 2 inches) near the 
appliance until a permanent air duct is installed. 
FIGURE 6  Draft Hood Spillage 










