A.O. Smith HW 300 Instruction Manual page 23

MODEL HW-300 BOILER
Input: 300,000 Btuh
Required Connector or Smoke Pipe Diameter
Total Vent Height (Measured in Feet Above Draft Hood)
Connector
10 15
Rise in Feet
1 10 10
2 10 10
3 10 10
4 or more
Total Vent Height (Measured in Feet Above Draft Hood)
Number
Total Input
if Units 10 15
Btuh x 1000
Combined
Manifold and Common Vent Diameter (in Inches)
2 600 14 12
3 900 16 14
4 1200 18 16
MODEL HW-399 BOILER
Input: 399,000 Btuh
Required Connector or Smoke Pipe Diameter
Total Vent Height (Measured in Feet Above Draft Hood)
Connector
10 15
Rise in Feet
1 12 12
2 12 12
3 12 10
4 or more 10 10
Total Vent Height (Measured in Feet Above Draft Hood)
Number
Total Input
if Units 10 15
Btuh x 1000
Combined
Manifold and Common Vent Diameter (in Inches)
2 798 14 14
3 1197 18 16
4 1596 20 20
MODEL HW-420 BOILER
Input: 420,000 Btuh
Required Connector or Smoke Pipe Diameter
Total Vent Height (Measured in Feet Above Draft Hood)
Connector
10 15
Rise in Feet
1 12 12
2 12 12
3 12 10
4 or more 10 10
Total Vent Height (Measured in Feet Above Draft Hood)
Number
Total Input
if Units 10 15
Btuh x 1000
Combined
Manifold and Common Vent Diameter (in Inches)
2 840 14 14
3 1260 18 16
4 1680 20 20
TABLE 14. COMBINED VENT SIZING TABLES
Draft Hood Outlet 8"
20 30 40 50 60 80
Connector Diameter (in Inches)
10 10 10 10 10 10
10 10 10 10 10 10
10 10 10 10 10 10
20 30 40 50 60 80
12 12 10 10 10 10
14 14 12 12 12 12
16 14 14 14 14 12
Draft Hood Outlet 10"
20 30 40 50 60 80
Connector Diameter (in Inches)
12 12 12 12 12 12
12 10 10 10 10 10
10 10 10 10 10 10
10 10 10 10 10 10
20 30 40 50 60 80
14 12 12 12 12 12
16 14 14 14 14 14
18 16 16 16 14 14
Draft Hood Outlet 10"
20 30 40 50 60 80
Connector Diameter (in Inches)
12 12 12 12 12 12
12 10 10 10 10 10
10 10 10 10 10 10
10 10 10 10 10 10
20 30 40 50 60 80
14 12 12 12 12 12
16 14 14 14 14 14
18 16 16 16 14 14
Input: 520,000 Btuh
Required Connector or Smoke Pipe Diameter
Connector
100
Rise in Feet
10 1
10 2
10 3
4 or more
Number
Total Input
100 if Units
Btuh x 1000
Combined
10 2 1040
12 3 1560
12 4 2080
5 2600
6 3120
7 3640
8 4160
Input: 660,000 or 670,000 Btuh
100
Required Connector or Smoke Pipe Diameter
12
Connector
10
Rise in Feet
10
1
10
2
3
100
4 or more
Number
12
Total Input
if Units
12
Btuh x 1000
Combined
14
2 1220
3 1830
4 2440
5 3050
6 3660
7 4270
8 4880
100
9 5490
10 6100
12
11 6710
10
12 7320
10
10
Example: Known: (5) model HW-670 boilers. (See illustration).
100
Connector rise - 2' (Note 1' is minimum). Total vent height 30'.
Problem: Determine diameter of connector, manifold and common
12
vent.
12
14
Procedure: Enter the top of the HW-670 table (total vent
height) at 30' and the side at 2' (connector rise). A 14"
connector diameter is indicated for each connector rise.
To determine the manifold and common vent size, enter table
on this page (total vent height) at 30 and the side at 5 boilers. A
manifold diameter of 24" (610 mm) is indicated.
23
MODEL HW-520 BOILER
Draft Hood Outlet 10"
Total Vent Height (Measured in Feet Above Draft Hood)
10 15 20 30 40 50
Connector Diameter (in Inches)
14 14 14 12 12 12
12 12 12 12 12 12
12 12 12 12 10 10
12 12 12 12 10 10
Total Vent Height (Measured in Feet Above Draft Hood)
10 15 20 30 40 50
Manifold and Common Vent Diameter (in Inches)
16 16 14 14 14 14
20 18 18 16 16 14
22 22 20 18 18 18
26 24 22 20 20 18
28 26 24 22 22 20
30 28 26 24 24 22
32 30 28 26 24 24
MODEL HW-670 BOILER
Draft Hood Outlet 12"
Total Vent Height (Measured in Feet Above Draft Hood)
10 15 20 30 40 50
Connector Diameter (in Inches)
16 14 14 14 14 14
14 14 14 14 14 12
14 14 12 12 12 12
12 12 12 12 12 12
Total Vent Height (Measured in Feet Above Draft Hood)
10 15 20 30 40 50
Manifold and Common Vent Diameter (in Inches)
18 18 16 16 14 14
22 20 20 18 18 16
26 24 22 20 20 18
28 26 26 24 22 22
32 28 28 26 24 24
34 32 30 28 26 24
36 34 32 30 28 26
38 36 34 30 30 28
40 38 36 32 30 30
42 38 38 34 32 30
46 44 40 38 36 34
60 80 100
12 12 12
12 12 12
10 10 10
10 10 10
60 80 100
12 12 12
14 14 14
16 16 14
18 18 18
20 18 18
22 20 20
22 22 20
60 80 100
14 14 14
12 12 12
12 12 12
12 12 12
60 80 100
14 14 14
16 16 14
18 18 16
20 20 18
22 22 20
24 22 22
26 24 24
28 26 24
28 26 26
28 28 26
34 32 30