LAARS Mighty Max HH (Sizes 320M - 400M) - Installation, Operation and Maintenance Instructions - Manual (Page 15)

Mighty Max Hydronic Boiler Page 15
2.13Air for Combustion and Ventilation
The boiler requires air for combustion and the
space around the boiler requires ventilation.
Combustion air can be provided by standard practices
as specified in the installation codes (ANSI Z223.1/
NFPA 54, in Canada, CSA B149.1 and local
applicable codes), or ducted directly to the boiler.
Ventilation air must be provided in either case.
2.13.1 Air From Room
Standard requirements for providing air for
combustion and ventilation are provided by ANSI
Z223.1/NFPA 54 and in Canada by CSA B149.1.
These codes require passages be provided for air flow
into the space where the boiler is installed. The size of
these passages is based on the firing rate of the boiler
and the path of air flow into the space. In general,
installations which take air from inside the building
require larger passages than those which take air
directly through an outside wall.
Failure to provide adequate combustion and
ventilation air can cause the boiler, and other
appliances occupying the same space, to operate with
dangerous and inefficient combustion, and can cause
overheating of the space. Be sure to provide air
passages in accordance with ANSI Z223.1/NFPA 54,
in Canada, CSA B149.1 and local applicable codes,
and do not permit any other condition, such as an
exhaust blower, to affect the air supply for combustion
and ventilation.
2.13.2 Ducted Combustion Air
Combustion air can be brought directly to the
boiler through a duct of suitable size and length (see
Table 7). Consult Laars about installations not covered
by Table 7.
Combustion air must be taken from out-of-doors
by means of the Laars side wall terminal.
Locate the terminal within 10 feet (3.0m) of the boiler
vent exhaust terminal, but no closer than 3 feet (0.9m)
(centerline distance).
Do not locate the air inlet terminal near a source
of corrosive chemical fumes (e.g., cleaning fluid,
chlorine compounds, etc.). Locate it so that it will not
be subject to damage by accident or vandalism. It must
be at least 7 feet (2.1m) above a public walkway.
Use single-wall galvanized pipe for the
combustion air duct. Route the duct to the heater as
directly as possible. Seal all joints with tape. Provide
adequate hangers. The heater must not support the
weight of the combustion air duct.
When combustion air is ducted to the boiler,
other provisions must be made for boiler room
ventilation. HH boilers lose less than 1 percent of their
input rating to the room, but other heat sources may be
present. Provide enough ventilation air to meet
comfort specifications. Make sure the ventilation air is
Figure 11. Ducted Combustion Air Conversion.
Ducted Combustion
Air Pipe
Inlet
Pipe
Adapter
Plate
Louvered
Plate
Boiler Size Assembly Number
320 20258101
400 20258102
Table 8. Combustion Air Assembly.
not directed at the boiler, water piping or other
equipment which could be damaged by freezing.
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