035-17468-001 Rev. A (801)
Unitary Products Group
15
NOTE:
If installing furnace at altitudes between 2000 - 4500
ft., the maximum allowable intake and vent pipe length must
be reduced by 10 ft. If the installation requires the maximum
allowable intake and vent pipe length, the furnace must be
converted for high altitude operation. Refer to the proper high
altitude application instruction for details.
1.
Long radius elbows are required for all units.
2.
Elbows are assumed to be 90 degrees. Two 45 degree
elbows count as one 90 degree elbow.
3.
Elbow count refers to combustion air piping and vent pip-
ing separately. For example, if the table allows for 5
elbows, this will allow a maximum of 5 elbows in the
combustion air piping and a maximum of 5 elbows in the
vent piping.
4.
Three vent terminal elbows (two for vent pipe and one for
air intake pipe) are already accounted for and should not
be counted in the allowable total indicated in the table.
See section on vent terminal. These parts are shown
shaded.
5.
Combustion air and vent piping must be of the same
diameter.
6.
All combustion air/vent pipe and fittings must conform to
American National Standards Institute (ANSI) standards
and American Society for Testing and Materials (ASTM)
standards D1785 (Schedule 40 PVC), D2665 (PVC-
DWV), F891 (PVC-DWV Cellular Core). D2241 (SDR-21
and SDR-26 PVC), D2261 (ABS-DWV), or F628 (Sched-
ule 40 ABS. Pipe cement and primer must conform to
ASTM Standards D2564 (PVC) or D2235 (ABS).
7.
The use of flexible connectors or no hub connectors in
the vent system is not allowed. This type connection is
allowed in the combustion air pipe near the furnace for
air conditioning coil accessibility.
VENT TERMINATION (2-PIPE)
Side wall horizontal vent terminals and roof mounted vertical
terminals may be field fabricated. Standard PVC/SRD fittings
may be used. Terminal configuration must comply as detailed
in this section.
NOTE:
Combustion air and vent pipes must terminate
together in the same atmospheric zone, either through a roof
or sidewall.
When selecting the location for combustion air/vent termina-
tion the following should be considered:
1.
Comply with all clearance requirements as listed below.
2.
Termination should be positioned where vent vapors will
not damage plants or shrubs or air conditioning equip-
ment.
3.
Termination should be located where it will not be
affected by wind gusts, light snow, airborne leaves or
allow recirculation of flue gases.
4.
Termination should be located where it will not be dam-
aged or exposed to flying stones, balls, etc.
5.
Termination should be positioned where vent vapors are
not objectionable.
VENT CLEARANCES (2-PIPE) U.S. ONLY
Dryer Vent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 ft.
Plumbing Vent Stack. . . . . . . . . . . . . . . . . . . . . . . . . . . 3 ft.
Gas Appliance Vent Terminal . . . . . . . . . . . . . . . . . . . .3 ft.*
From any mechanical fresh air intake. . . . . . . . . . . . . . 1 ft.
From any door, window or non-mechanical fresh air or
combustion air intake . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ft.
Above grade and anticipated snow depth . . . . . . . . . . 1 ft.
Above grade when adjacent to public walkway . . . . . . 7 ft.
From electric, gas meters, regulators and relief equipment -
min. horizontal distance . . . . . . . . . . . . . . . . . . . . . . . . 4 ft.
* Does not apply to multiple installations of this furnace
model. Refer to multi-unit vent terminations.
NOTE:
Consideration must be given for degradation of build-
ing materials by flue gases.
Table 4:
INTAKE/VENT PIPING - 2 PIPE SYSTEM
Upflow
Models
Pipe
Size
Max. Elbows vs. One Way Vent
Length (Ft.)
1
1.
Elbow count does not include the elbows required for
the termination. See Step 4 under Combustion Air/Vent
Pipe Sizing
5 - 40
45
50
75
60 / 55 / 1200 / B
2”
6
5
4
N/A
80 / 75 / 1600 / C
100 / 95 / 2000 / C
60 / 55 / 1200 / B
3”
8
7
6
5
80 / 75 / 1600 / C
100 / 95 / 2000 / C
120 / 112 / 2000 / D
3” Only
6
5
4
N/A
Table 5:
INTAKE/VENT PIPING - 2 PIPE SYSTEM
Downflow/Horizontal
Models
Pipe
Size
Max. Elbows vs. One Way Vent
Length (Ft.)
1
1.
Elbow count does not include the elbows required for
the termination. See Step 4 under Combustion Air/Vent
Pipe Sizing
5 - 30
35
40
60
80 / 75 / 1200 / B
2”
6
5
4
N/A
80 / 75 / 1200 / B
3”
8
7
6
5
120 / 112 / 2000 / D
3” Only
6
5
4
N/A
NOTE:
Accessory concentric intake/vent terminations,
models 1CT0302 and 1CT0303 are available and
approved for use with these furnaces. Refer to instructions
035-14287-000 for installation details.
In Canada, refer to CAN/CGA-B149.1 or .2 Installation
Code (latest edition - Venting Systems and Air Supply)
