Laars NeoTherm NTH Installation and operation instructions manual - page 8
LAARS Heating Systems
Page 8
SECTION 2.
Venting and Combustion Air
2.1 Combustion Air
NeoTherm boilers and water heaters must have
provisions for combustion and ventilation air in
accordance with the applicable requirements for
Combustion Air Supply and Ventilation in the National
Fuel Gas Code, ANSI Z223 1; or in Canada, the Natural
Gas and Propane Installation Code, CSA B149.1. All
applicable provisions of local building codes must also
be adhered to.
A NeoTherm unit can take combustion air from
the space in which it is installed, or the combustion
air can be ducted directly to the unit. Ventilation air
must be provided in either case.
2.1.1 Combustion Air From Room
In the United States, the most common
requirements specify that the space shall communicate
with the outdoors in accordance with method 1 or 2,
which follow. Where ducts are used, they shall be of the
same cross-sectional area as the free area of the
openings to which they connect.
Method 1: Two permanent openings, one
commencing within 12" (300mm) of the top and one
commencing within 12" (300mm) of the bottom, of the
enclosure shall be provided. The openings shall
communicate directly, or by ducts, with the outdoors or
spaces that freely communicate with the outdoors.
When directly communicating with the outdoors, or
when communicating to the outdoors through vertical
ducts, each opening shall have a minimum free area of 1
square inch per 4000 Btu/hr (550 square mm/kW) of
total input rating of all equipment in the enclosure.
When communicating to the outdoors through
horizontal ducts, each opening shall have a minimum
free area of not less than 1 square inch per 2000 Btu/hr
(1100 square mm/kW) of total input rating of all
equipment in the enclosure.
Method 2: One permanent opening, commencing
within 12" (300mm) of the top of the enclosure, shall be
permitted. The opening shall directly communicate with
the outdoors or shall communicate through a vertical or
horizontal duct to the outdoors or spaces that directly
communicate with the outdoors and shall have a
minimum free area of 1 square inch per 3000 Btu/hr
(734 square mm/kW) of the total input rating of all
equipment located in the enclosure. This opening must
not be less than the sum of the areas of all vent
connectors in the confined space.
Other methods of introducing combustion and
ventilation air are acceptable, providing they conform to
the requirements in the applicable codes listed above.
In Canada, consult local building and safety codes or,
in absence of such requirements, follow CAN/CGA B149.
NeoTherm Boilers must never be installed on
carpeting. The location for the appliance should be
chosen with regard to the vent pipe lengths and external
plumbing and on a level surface. The unit shall be
installed such that the gas ignition system components
are protected from water (dripping, spraying, rain, etc.)
during operation and service (circulator replacement,
control replacement, etc.). When vented vertically, the
NeoTherm must be located as close as practical to the
vertical section of the vent. If the vent terminal and/or
combustion air terminal terminate through a wall, and
there is potential for snow accumulation in the local
area, both terminals should be installed at an appropriate
level above grade or the maximum expected snow line.
The dimensions and requirements that are shown
in
Table 1
should be met when choosing the locations
for the appliance.
1.8 Locating Appliance for Correct Vent
Distance from Outside Wall or
Roof Termination
The forced draft combustion air blower in the
appliance has sufficient power to vent properly when
the guidelines in
Table 2
are followed.
NOTE: When located on the same wall, the NeoTherm
combustion air intake terminal must be installed a
minimum of 12" (30cm) below the exhaust vent terminal.
For concentric vent terminal kit (optional), follow
installation instructions included with the kit.
REQUIRED CLEARANCE FROM SUGGESTED SERVICE
APPLIANCE
COMBUSTIBLE MATERIAL
ACCESS CLEARANCE
SURFACE
IN.
CM
IN.
CM
Left Side
1
2.5
1
2.5
Right Side
1
2.5
12
31
Top
1
2.5
24
61
Back
1
2.5
6
15
Closet, Front
1
2.5
6
15
Alcove, Front
1
2.5
24
61
Vent
0
0
–
–
Table 1. Clearances.
SIZE
MAX EQUIVALENT
*
VENT LENGTH PVC/CPVC
(EACH INTAKE AND EACH EXHAUST)
2" DIA / 5.1CM
3" DIA / 7/6CM
4" DIA / 10.2CM
80
40 ft 6.1M
100 ft 30.5M
n/a
105
40 ft 6.1M
100 ft 30.5M
n/a
150
n/a
100 ft 30.5M
n/a
210
n/a
100 ft 30.5M
n/a
285
n/a
20 ft 6.1M
100 ft 30.5M
399
n/a
n/a
100 ft 30.5M
500N
n/a
n/a
100 ft 30.5M
500P
n/a
n/a
80 ft 24.4M
* Each 90° fitting = 5 equivalent feet 1.5M
Table 2. Vent / Air Pipe Sizes.