935SA: Installation, Start-up, Operating and Service Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
38
NOTE:
Maximum Equivalent Vent Length (MEVL) includes standard and concentric vent termination and does NOT include elbows. Use
-
Deductions from Maximum Equivalent Vent Length to determine allowable vent length for each application.
A13110
NOTES
:
1. Use only the smallest diameter pipe possible for venting. Over-sizing may cause flame disturbance or excessive vent terminal icing or freeze-up.
2. NA - Not allowed
. Pressure transducer w
ill not close, or flame disturbance may result.
3. Vent sizing for Canadian installations over 4500 ft. (1370 M) above sea level are subject to acceptance by the local authorities having jurisdiction.
4. Size both the combustion air and vent pipe independently, then use the larger size for both pipes.
5. Assume the two 45
_
elbows equal one 90
_
elbow. Wide radius elbows are desirable and may be required in some cases.
6. Elbow and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.
7. The minimum pipe length is 5 ft. (2 M) linear feet (meters) for all applications.
8. Use 3-in. (76 mm) diameter vent termination kit for installations requiring 4-in. (102 mm) diameter pipe.
Table 17 – Maximum Allowable Exposed Vent Length in Unconditioned Space - Ft.
Unit Size
40,000 BTUH
60,000 BTUH
Winter
Design
Temp °F
Pipe Dia.
in.
Uninsulated
3/8-in.
Insulation
1/2-in.
Insulation
Uninsulated
3/8-in. Insulation
1/2-in. Insulation
1 ½
2
2 ½ 1 ½
2
2 ½ 1 ½
2
2 ½
1 ½
2
2 ½ 3
1 ½
2
2 ½
3
1 ½
2
2 ½ 3
20
20
20
20
20
50
45
20
60
50 20
30
30
25
20
75
65
60
20
85
75
65
0
10
5
5
20
25
20
20
30
25 15
15
10
10
20
40
30
25
20
45
40
30
-20
5
20
15
10
20
20
15 10
5
20
25
20
15
20
30
25
20
-40
15
10
5
15
15
10 5
20
15
15
10
20
20
15
10
Unit Size
80,000 BTUH
Winter
Design
Temp
°F
Pipe Dia.
in.
Uninsulated
3/8-in. Insulation
1/2-in. Insulation
1 ½
2
2 ½
3
4
1 ½
2
2 ½
3
4
1 ½
2
2 ½
3
4
20
15
40
40
35
30
15
50
90
75
65
15
50
70
70
70
0
15
20
15
10
5
15
50
45
35
30
15
50
50
40
35
-20
15
10
5
15
35
30
20
15
15
40
30
25
15
-40
10
5
15
25
20
15
5
15
30
25
20
10
Unit Size
100,000 BTUH
Winter
Design
Temp °F
Pipe Dia.
in.
Uninsulated
3/8-in. Insulation
1/2-in. Insulation
2
2 ½
3
4
2
2 ½
3
4
2
2 ½
3
4
20
20
50
40
35
20
80
95
80
20
80
105
90
0
20
20
15
10
20
55
45
35
20
65
55
45
-20
15
10
5
20
35
30
20
20
45
35
25
-40
10
5
20
25
20
10
20
30
25
15
Table 18 – Maximum Equivalent Vent Length - Ft.
Unit Size
40,000
60,000
80,000
100,000
Altitude
(feet)
Pipe Dia.
(in)
1
½
2
2
½
1
½
2
2
½
3
1
½
2
2
½
3
4
2
2
½
3
4
0-2000
40 155 185
20
100
175
200
15
55
130
175
200
20
80
175
200
2001-3000 35 150 175
95
165
185
10
49
125
165
185
15
75
165
185
3001-4000 30 135 160
16
90
155
175
115
155
175
155
175
4001-4500 25 130 155
15
85
150
170
44
110
150
165
10
70
170
4501-5000
125 145
80
145
165
44
110
145
160
65
150
165
5001-5400 20 120 130
75
140
155
41
100
135
150
140
155
Table 19 – Deductions from Maximum Equivalent Vent Length - Ft. (M)
Pipe Diameter (in):
1-1/2
2
2-1/2
3
4
Mitered 90º Elbow
8
(2.4)
8
(2.4)
8
(2.4)
8
(2.4)
8
(2.4)
Medium Radius 90º Elbow
5
(1.5)
5
(1.5)
5
(1.5)
5
(1.5)
5
(1.5)
Long Radius 90º Elbow
3
(0.9)
3
(0.9)
3
(0.9)
3
(0.9)
3
(0.9)
Mitered 45º Elbow
4
(1.2)
4
(1.2)
4
(1.2)
4
(1.2)
4
(1.2)
Medium Radius 45º Elbow
2.5
(0.8)
2.5
(0.8)
2.5
(0.8)
2.5
(0.8)
2.5
(0.8)
Long Radius 45º Elbow
1.5
(0.5)
1.5
(0.5)
1.5
(0.5)
1.5
(0.5)
1.5
(0.5)
Tee
16
(4.9)
16
(4.9)
16
(4.9)
16
(4.9)
16
(4.9)
Concentric Vent Termination
NA
0
(0.0)
NA
0
(0.0)
NA
Standard Vent Termination
0
(0.0)
0
(0.0)
0
(0.0)
0
(0.0)
0
(0.0)
Long
Medium
Mitered
Concentric
Standard 2-in., 3-in., or
optional 4-in. termination.
ELBOW CONFIGURATIONS
VENT TERMINAL CONFIGURATIONS
