lp-445-r4 Rev. 006 Rel. 027 Date 7.21.20
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2. Room and Indoor Combustion Ventilation Requirements
When using an indoor combustion air installation, the mechanical
room MUST be provided with properly sized openings, and/or be
of sufficient volume to assure adequate combustion air and proper
ventilation for all gas fired appliances in the mechanical room
to assure adequate combustion air and proper ventilation. The
requirements shown here are for the boiler only. Additional gas fired
appliances in the mechanical room will require an increase in the net
free area and/or volume to supply adequate combustion air for all
appliances. This must be done in accordance with the National Fuel
Gas Code, NFPA 54 / ANSI Z223.1.
This boiler can be vented using mechanical room air only for
combustion. No combustion air openings are needed when the
boiler is installed in a space with a volume NO LESS than 50 cubic
feet per 1,000 BTU/hr of all installed gas fired appliances and the
building MUST NOT BE of “Tight Construction”.
TIGHT CONSTRUCTION:
A building with less than .4 ACH (air
changes per hour). For buildings of “Tight Construction”, provide air
openings into the building from the outside.
Indoor and outdoor combustion air may be combined by applying
a ratio of available volume to required volume times the required
outdoor air opening(s) size(s). This must be done in accordance with
the National Fuel Gas Code, NFPA 54 / ANSI Z223.1.
1. If air is taken directly from outside the building with no duct,
provide two permanent openings to the mechanical room each
with a net free area of one square inch per 4000 BTU/hr input. See
Figure 17.
2. If combustion and ventilation air is taken from the outdoors using
a duct to deliver the air to the mechanical room, each of the two
openings should be sized based on a minimum free area of one
square inch per 2000 BTU/hr input. See Figure 18.
3. If air is taken from another interior space combined with the
mechanical room:
a. Two spaces on same story: Each of the two openings specified
should have a net free area of one square inch for each 1000 BTU/
hr input, but not less than 100 square inches.
b. Two spaces on different stories: One or more openings should
have a net free area of two square inches per 1000 BTU/hr.
See Figure 19 for reference.
4. If a single combustion air opening is provided to bring combustion
air in directly from the outdoors, the opening must be sized based
on a minimum free area of one square inch per 3000 BTU/hr. This
opening must be located within 12” of the top of the enclosure. See
Figure 20.
Combustion air requirements are based on the latest edition of
the National Fuel Gas Code, NFPA 54 / ANSI Z223.1, CGA Standard
CAN/CSA B149.1 in Canada. Check all local code requirements for
combustion air.
All dimensions based on net free area in square inches. Metal
louvers or screens reduce the free area of a combustion air opening
a minimum of approximately 25%. Check with louver manufacturers
for exact net free area of louvers.
Where two openings are provided, one must be within 12” of the
ceiling, and one must be within 12”of the floor of the mechanical
room. Each opening must have a net free area as specified in Table
13. Single openings shall commence within 12” of the ceiling. The
minimum dimension of air openings should not be less than 3”.
Figure 17 - Combustion Air from Outdoors
Figure 18 - Combustion Air through Ductwork
Figure 19 - Combustion Air from Indoors
Figure 20 - Combustion Air from Outdoors - Single Opening
Содержание MODCON500 FS
Страница 34: ...lp 445 r4 Rev 006 Rel 027 Date 7 21 20 34 Figure 26 Cascade Master and Follower Wiring ...
Страница 61: ...lp 445 r4 Rev 006 Rel 027 Date 7 21 20 61 Figure 34 Water Side Replacement Parts All Models ...
Страница 62: ...lp 445 r4 Rev 006 Rel 027 Date 7 21 20 62 Figure 35 Cabinet Replacement Parts All Models See Table ...
Страница 65: ...lp 445 r4 Rev 006 Rel 027 Date 7 21 20 65 Maintenance Notes ...
