035-20646-001 Rev. A (1004)
14
Unitary Products Group
*. Elbow count does not include the elbows required for the termination. See Step 4 under Combustion Air/Vent Pipe Sizing.
NOTE:
NOTE: If installing furnace at altitudes between 2000 - 4500 ft.,
(1609.6 - 1371.6 m) intake and vent pipe length must be
reduced by 10 ft. (3.05 m) If the installation requires the maxi-
mum allowable intake and vent pipe length, the furnace must be
converted for high altitude operation.
COMBUSTION AIR AND VENT PIPING ASSEMBLY
The final assembly procedure for the combustion air and vent piping is
as follows:
1.
Cut piping to the proper length beginning at the furnace.
2.
Deburr the piping inside and outside.
3.
Chamfer (bevel) the outer edges of the piping.
4.
Dry-fit the vent piping assembly from the furnace to the outside ter-
mination checking for proper fit support and slope.
5.
Dry-fit the combustion air piping assembly checking for proper fit,
support and slope on the following systems:
A.
Sealed combustion air systems from the furnace to the out-
side termination.
B.
Ventilated combustion air systems from the furnace to the
attic or crawl space termination.
6.
Disassemble the combustion air and vent piping, apply cement
primer and the cement per the manufactures instructions. Primer
and cement must conform to ASTM D2564 for PVC, or ASTM
D2235 for ABS piping.
7.
All joints must provide a permanent airtight and watertight seal.
8.
Support the combustion air and vent piping such that it is angled a
minimum of 1/4” per foot (0.635 cm/m) so that condensate will flow
back towards the furnace. Piping should be supported with pipe
hangers to prevent sagging.
9.
Seal around the openings where the combustion air and / or vent
piping pass through the roof or sidewalls.
COMBUSTION AIR / VENT CLEARANCES
IMPORTANT:
The vent must be installed with the following minimum
clearances, and must comply with local codes and requirements.
TABLE 10:
Combustion Air Supply and Vent Piping
MAXIMUM ELBOWS AND VENT LENGTHS
Models Input
BTUH (kW)
Pipe Size
Inches (mm)
Maximum Number of Elbows*
Minimum
Length
1 2 3 4 5 6 7 8
60,000 (17.6)
1-1/2 (38)
15
10
N/A
N/A
N/A
N/A
N/A
N/A
1.5
60,000 (17.6)
2 (51)
60
55
50
45
40
35
25
15
1.5
60,000 (17.6)
3 (76)
85
80
75
70
65
60
50
40
10
80,000 (23.4)
2 (51)
60
55
50
45
40
35
25
15
1.5
80,000 (23.4)
3 (76)
85
80
75
70
65
60
50
40
10
80,000 (23.4)
2 (51)
60
55
50
45
40
35
25
15
1.5
80,000 (23.4)
3 (76)
85
80
75
70
65
60
50
40
10
100,000 (29.3)
2 (51)
25
20
15
10
N/A
N/A
N/A
N/A
1.5
100,000 (29.3)
3 (76)
80
75
70
65
60
55
45
35
1.5
120,000 (35.1)
3 (76)
55
50
45
40
35
25
15
N/A
1.5
Solvent cements are flammable and must be used in well-ventilated
areas only. Keep them away from heat, sparks and open flames.
Do not breathe vapors and avoid contact with skin and eyes.