Size The Vent And Combustion Air Pipes - Carrier 120 Series Operating Instructions Manual

4. Termination or termination kit should be positioned where it
will not be damaged by or subjected to foreign objects such
as stones, balls, etc.
5. Termination or termination kit should be positioned where
vent vapors are not objectionable.
Direct Vent / 2-Pipe System
Direct vent (2- -pipe) vent and combustion air pipes must terminate
outside the structure. See Fig. 45 For references to vent clearances
re. Allowable vent and combustion air terminations are shown in
Fig. 47.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow the instructions outlined below for each
appliance being placed into operation could result in carbon
monoxide poisoning or death.
For all venting configurations for this appliance and other gas
appliances placed into operation for this structure, provisions
for adequate combustion, ventilation, and dilution air must be
provided in accordance with:
U.S.A. Installations: Section 9.3 NFPA 54/ANSI Z223.1
- -2012, Air for Combustion and Ventilation and applicable
provisions of the local building codes.
Canadian Installations: Part 8 of CAN/CSA- -B149.1- -10.
Venting Systems and Air Supply for Appliances and all
authorities having jurisdiction.
Ventilated Combustion Air
The vent pipe for a Ventilated Combustion Air System must
terminate outdoors. See Fig. 46 For references to vent clearances
required by National code authorities. Allowable vent terminations
are shown in Fig. 48. The combustion air pipe terminates in a
well- -ventilated attic or crawl space. Follow the clearances as
shown in Fig. 50.
The combustion air pipe cannot terminate in attics or crawl spaces
that use ventilation fans designed to operate in the heating season.
If ventilation fans are present in these areas, the combustion air
pipe must terminate outdoors as a Direct Vent System.
Termination Requirements for the Provinces of Alberta and
Saskatchewan
The Provinces of Alberta and Saskatchewan require a minimum
unobstructed distance of 4 ft. (1.2 M) from the foundation to the
property line of the adjacent lot for vent termination of any
appliance with an input over 35,000 btuh. If there is less than 4 ft.
(1.2 M) of unobstructed distance to the property line of the
adjacent lot, no type of vent termination is permitted for appliances
with inputs greater than 35,000 btuh.
There are no additional restrictions on unobstructed distances
greater than 8 ft. (2.4 M). All single, two-pipe and concentric vents
may be used, providing all other Code and manufacturer's
requirements in these instructions are adhered to. Refer to the
appropriate Vent Termination section above for locating the vent
termination
If the unobstructed distance from the foundation to the property
line of the adjacent lot is no less than 4 ft. (1.2 M) and no greater
than 8 ft. (2.4 M), it will be necessary to re-direct the flue gas
plume. In this situation, a concentric vent kit cannot be used. A
2-pipe termination (or single pipe termination when permitted with
ventilated combustion air applications) that re-directs the flue gas
away by use of an elbow or tee, certified to ULC S636 from the
adjacent property line must be used. See Fig. 49.
The concentric vent kit currently cannot be modified to attach an
elbow to the vent portion of the rain cap. A tee attached to the rain
cap could potentially direct the flue gas plume toward the intake air
stream and contaminate the incoming combustion air for the
furnace.
Refer to Fig. 49 for terminations approved for use in Alberta and
Saskatchewan.

Size the Vent and Combustion Air Pipes

General
APPROVED 2--- PIPE TERMINATION
VENT OR
COMBUSTION AIR
PIPE DIAMETERS 2-in.
1 1/2-in. X
2-in. X
2 1/2-in. N/A
3-in. N/A
4-in. N/A
Note: Optional accessory 2-pipe termination brackets are sized for 2-in.
and 3-in. pipe. If a termination bracket is required for a 4-in. termination,
field fabricate the necessary brackets and clamps.
Furnace combustion air and vent pipe connections are sized for
2-in. (50 mm ND) PVC/ABS DWV pipe. The combustion air and
vent pipe connections also accommodate 60 mm polypropylene
venting systems with outside diameters of approximately 60 mm
(2- -3/8 inches). Any pipe diameter change should be made outside
furnace casing in vertical pipe. Any change is diameter to the pipe
must be made as close to the furnace as reasonably possible. See
Fig. 38.
The Maximum Vent Length for the vent and combustion air pipe
(when used) is determined from the Maximum Equivalent Vent
Length in Table 15 or 17, minus the number of fittings multiplied
by the deduction for each type of fitting used from Table 16.
NOTICE
OPTIONAL CONFIGURATION FOR COMBUSTION
AIR INLET PIPE
In applications where there is a risk of excessive moisture
entering the combustion air inlet pipe, a moisture trap may be
added to the inlet pipe to help prevent moisture from entering
the furnace from the combustion air inlet pipe. See Fig. 52.
When sizing venting systems, the equivalent length of the
optional moisture trap (15 feet/5 M) must be taken into
account.
Optional Combustion Air Inlet Moisture Trap
As an option to prevent moisture from trickling into the furnace
vestibule, a trap can be installed in the intake air pipe near the
furnace. Connecting a drain line to the trap is optional as trace
amounts of moisture will evaporate into the intake air stream. If the
combustion air inlet is located near a moisture exhaust duct, or
there are other concerns of excessive moisture being drawn into the
combustion air inlet, it is encouraged to connect a drain line to the
trap.
The trap can be constructed from a running tee of the same
diameter of the intake air pipe with EITHER a removable cap
attached to a 6-inch long pipe connected to the tee or the External
Vent Trap Kit to help prevent contaminants from entering the
furnace. See Fig. 52.
The External Vent Trap Kit accessory may be used as a trap for the
combustion air inlet pipe if a large amount of moisture must be
removed. The drain line may be connected to the same drain as the
furnace condensate and the evaporator coil condensate line ONLY
if the inlet air trap drain and the evaporator coil drain empty into an
open segment of pipe above the drain. See Fig.12. When using
the External Vent Trap Kit, refer to those instructions for proper
drain connections.
The tee may also be connected to the intake air pipe on the side of
the casing. See Fig. 52.
44
FITTINGS
3-in. 4-in.
N/A N/A
N/A N/A
X N/A
X N/A
X X