Mighty Max Hydronic Boiler
Page 15
2M-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 CAN/CGA
B149.1 or .2. 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, CAN/CGA B149.1 or .2 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.
2M-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
not directed at the boiler, water piping or other
equipment which could be damaged by freezing.
2M-3. Conversion for Ducted
Combustion Air
The conversion to ducted combustion air
requires the parts listed in Table 8. Follow these
procedures to convert the heater (see Figure 11):
Figure 11. Ducted Combustion Air Conversion.
Ducted Combustion
Air Pipe
Inlet
Pipe
Adapter
Plate
Louvered
Plate
Boiler Size
Assembly Number
320
20258101
400
20258102
520
20258103
625
20258104
775
20258105
1000
20258106
Table 8. Combustion Air Assembly.
