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Table 4—Maximum Allowable Vent Pipe Length (Ft)
ALTITUDE
UNIT SIZE
9001 to 10,000†
* Wide radius elbow.
† Vent sizing for Canadian installations over 4500 ft (1370 m) above sea level are subject to acceptance by the local authorities having jurisdiction.
NA—Not Allowed; pressure switch will not make.
NOTES:
1. Do not use pipe size greater than those specified in table or incomplete combustion, flame disturbance, or flame sense lockout may occur.
2. Assume two 45° elbows equal one 90° elbow. Long radius elbows are desirable and may be required in some cases.
3. Elbows and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.
4. The minimum pipe length is 5 ft for all applications.
Table 5—Maximum Allowable Exposed Vent Pipe Length (Ft) With Insulation in
WINTER DESIGN
UNIT
TEMPERATURE
SIZE
(°F)
20
040
0
-20
20
060
0
-20
20
080
0
-20
20
100
0
-20
20
120
0
-20
* Pipe length (ft) specified for maximum pipe lengths located in unconditioned spaces. Pipes located in unconditioned space cannot exceed total allowable pipe length
as specified in Table 4.
† Insulation thickness based on R value of 3.5 per in.
Inducer housing outlet cap must be installed and fully seated
against inducer housing. Clamp must be tightened to prevent
any condensate leakage. Failure to follow this warning could
result in electrical shock, fire, personal injury, or death.
3. Install pipe support (factory-supplied in loose parts bag) into
selected furnace casing vent pipe hole. Pipe support should be
positioned at bottom of casing hole.
4. Insert 2-in. diameter pipe into inducer housing through neo-
prene coupling and clamp in inducer housing. Tighten clamp.
Vent pipe must be installed and fully seated against inducer
housing. Clamp must be tightened to prevent any condensate
leakage. Failure to follow this warning could result in
electrical shock, fire, personal injury, or death.
NOTE: A 2-in. diameter pipe must be used within the furnace
casing. Make all pipe diameter transitions outside furnace casing.
VENT PIPE
DIAMETER (IN.)
1-1/2
040-08
040-12
2
060-08
036060
2
060-16
080-12
2
080-16
2-1/2
080-20
2-1/2
100-16
100-20
3
120-20
3*
Winter Design Temperature Ambient*
MAX PIPE
DIAMETER
(IN.)
1-1/2
1-1/2
1-1/2
2
2
2
2-1/2
2-1/2
2-1/2
3
3
3
3
3
3
Continued
NUMBER OF 90° ELBOWS
1
2
3
42
37
32
57
55
53
45
40
38
30
25
14
57
55
53
21
13
5
54
49
44
39
37
35
INSULATION THICKNESS (IN.)†
0
3/8
31
56
16
34
9
23
45
70
25
51
16
36
55
70
31
61
20
43
61
70
33
65
20
45
70
70
40
70
26
55
VENT EXTENSION PIPE
Some furnaces are supplied with a PVC vent extension pipe
(2-in. diameter by 12-in. long). This pipe has a built-in
channel to assist vent condensate disposal. When this vent
extension pipe is supplied, it must be used to connect the field
vent pipe to furnace inducer housing on ALL upflow and
downflow applications.
NOTE: See label on vent extension pipe for proper installation.
This pipe may be shortened if an elbow is used to connect vent
extension tube to field-installed vent pipe.
5. Working from furnace to outside, cut pipe to required
length(s).
6. Deburr inside and outside of pipe.
7. Chamfer outside edge of pipe for better distribution of primer
and cement.
8. Clean and dry all surfaces to be joined.
9. Check dry fit of pipe and mark insertion depth on pipe.
NOTE: It is recommended that all pipes be cut, prepared, and
preassembled before permanently cementing any joint.
27
4
5
27
25
51
49
33
31
9
7
51
49
NA
NA
39
34
33
31
1/2
3/4
63
70
39
47
27
34
70
70
58
70
42
51
70
70
69
70
49
61
70
70
70
70
52
65
70
70
70
70
64
70
6
20
47
29
NA
47
NA
29
29
1
70
54
39
70
70
60
70
70
70
70
70
70
70
70
70
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