Laars NeoTherm NTH Installation And Operation Instructions Manual - page 10
LAARS Heating Systems
Page 10
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.
2.1.2 Intake Combustion Air
The combustion air can be taken through the wall, or
through the roof. When taken from the wall, it must be
taken from out-of-doors by means of the LAARS
horizontal wall terminal, shown in
Table 3
. See
Table 2
to
select the appropriate diameter air pipe. When taken from
the roof, a field-supplied rain cap or an elbow arrangement
must be used to prevent entry of rain water (see
Figure10
).
Use ABS, PVC, CPVC or galvanized pipe for the
combustion air intake (see
Table 4
), sized per
Section 1.8
.
Route the intake to the boiler as directly as possible. Seal
all joints. Provide adequate hangers. The unit must not
support the weight of the combustion air intake pipe.
Maximum linear pipe length allowed is shown in
Table 2
.
Subtract 5 allowable linear ft. (1.5m) for every elbow used.
The connection for the intake air pipe is at the top of
the unit.
In addition to air needed for combustion, air shall
also be supplied for ventilation, including air required for
comfort and proper working conditions for personnel.
2.2 Venting
WARNING
Failure to use CPVC or stainless steel venting for the
first 20" (285-500) / 30" (80-210) of vent material or
for any part of the venting that is installed inside a
closet may lead to property damage, personal injury
or death. The proper length of this material is
supplied with boiler.
WARNING
Failure to use the appropriate vent material,
installation techniques, glues/sealants could lead to
vent failure causing property damage, personal injury
or death.
WARNING
All venting must be installed according to this manual
and any other applicable local codes, including but
not limited to, ANSI Z223.1/NFPA 54, CSA B149.1,
CSAB149.2 and ULC-S636. Failure to follow this
manual and applicable codes may lead to property
damage, severe injury, or death.
The flue temperature of the NeoTherm changes
dramatically with changes in operating water
temperature. Therefore, it is necessary to assess the
application of the boiler to determine the required
certified vent class. If the NeoTherm is installed in
an application where the ambient temperature is
elevated, and/or installed in a closet/alcove, CPVC or
stainless steel material is required. If the system
temperatures are unknown at the time of
installation, class IIB or higher venting material is
recommended.
Figure 10. Combustion Air and Vent Through Roof.