1-13
INSTALLATION
SL 35-199, SL 45-260 MODULATING GAS BOILERS
1.4.8 “Indoor Air” Combustion Air Intake
An “Indoor Combustion Air installation”, as described herein, is one in which air
for combustion is taken from the ambient air around the boiler.
To support combustion, an ample air supply is required. This may require
direct openings in the boiler room to the outside. If the boiler is not in a room
adjacent to an outside wall, air may be ducted from outside wall openings.
Provisions for combustion and ventilation air must be made as follows:
• in the USA, in accordance with the National Fuel Gas Code, ANSI Z223.1
(latest edition), or applicable provisions of the local building codes
• in Canada, in compliance with B149.1-10
1.4.9 Combustion Air Filtration
If combustion air contamination from ingested particulate matter may be a
concerninanyinstallation,anoptionalairintakeltermaybeinstalled.IBC
suppliedairintakeltershaveaknownpressuredropandfoulingfactorand
should be used as a component of the combustion air system according to the
allowable intake length in Table 4.
1.4.10 Closet Installations
Forinstallationsinaconnedspace(suchasacloset),ventilationopeningsmay
be needed through a door or wall to prevent excessive heat from building up
inside the space.
The boiler shall not be exposed to ambient conditions above 122°F (50°C) or
below 32°F (0°C).
NOTE
Combustion fan
blockages can occur when
environmental particulate and
foreign matter contaminants
(leaves, dust, dandelion &
cottonwood uff, etc) are
drawn into the air intake. In
areas where this problem is
suspected to be an issue,
our optional air intake lter
should be installed.
Filters should be checked
and cleaned or replaced on
a regular schedule based on
the severity of the problem.
Figure 14: Direct vent - intake, exhaust system with optional air intake lter (ltration may
also be used on indoor air applications as required)
P172A Filter assembly