A.O. Smith HW 610 warranty Combined Vent Sizing Tables

TABLE 5, COMBINED VENT SIZING TABLES

MODEL HW-300 BOILER

	Input: 300,000 Btuh							Draft Hood Outlet 8"
	Required Connector or					Smoke Pipe Diameter
	Connector		Total Vent Height (Measured in Feet Above Draft Hood)
		10		15	20		30	40	50	60	80	100
	Rise in Feet
						Connector Diameter (in Inches)
	1	10		10	10		10	10	10	10	10	10
	2	10		10	10		10	10	10	10	10	10
	3	10		10	10		10	10	10	10	10	10
	4 or more
Number	Total Input		Total Vent Height (Measured in Feet Above Draft Hood)
if Units		10		15	20		30	40	50	60	80	100
	Btuh x 1000
Combined				Manifold and Common Vent Diameter (in Inches)
2	600	14		12	12		12	10	10	10	10	10
3	900	16		14	14		14	12	12	12	12	12
4	1200	18		16	16		14	14	14	14	12	12
		MODEL HW-399 BOILER
	Input: 399,000 Btuh							Draft Hood Outlet 10"
	Required Connector or					Smoke Pipe Diameter
	Connector		Total Vent Height (Measured in Feet Above Draft Hood)
		10		15	20		30	40	50	60	80	100
	Rise in Feet
						Connector Diameter (in Inches)
	1	12		12	12		12	12	12	12	12	12
	2	12		12	12		10	10	10	10	10	10
	3	12		10	10		10	10	10	10	10	10
	4 or more	10		10	10		10	10	10	10	10	10
Number	Total Input		Total Vent Height (Measured in Feet Above Draft Hood)
if Units		10		15	20		30	40	50	60	80	100
	Btuh x 1000
Combined				Manifold and Common Vent Diameter (in Inches)
2	798	14		14	14		12	12	12	12	12	12
3	1197	18		16	16		14	14	14	14	14	12
4	1596	20		20	18		16	16	16	14	14	14
		MODEL HW-420 BOILER
	Input: 420,000 Btuh							Draft Hood Outlet 10"
	Required Connector or					Smoke Pipe Diameter
	Connector		Total Vent Height (Measured in Feet Above Draft Hood)
		10		15	20		30	40	50	60	80	100
	Rise in Feet
						Connector Diameter (in Inches)
	1	12		12	12		12	12	12	12	12	12
	2	12		12	12		10	10	10	10	10	10
	3	12		10	10		10	10	10	10	10	10
	4 or more	10		10	10		10	10	10	10	10	10
Number	Total Input		Total Vent Height (Measured in Feet Above Draft Hood)
if Units		10		15	20		30	40	50	60	80	100
	Btuh x 1000
Combined				Manifold and Common Vent Diameter (in Inches)
2	840	14		14	14		12	12	12	12	12	12
3	1260	18		16	16		14	14	14	14	14	12
4	1680	20		20	18		16	16	16	14	14	14
		MODEL HW-520 BOILER
	Input: 520,000 Btuh							Draft Hood Outlet 10"
	Required Connector or					Smoke Pipe Diameter
	Connector		Total Vent Height (Measured in Feet Above Draft Hood)
		10		15	20		30	40	50	60	80	100
	Rise in Feet
						Connector Diameter (in Inches)
	1	14		14	14		12	12	12	12	12	12
	2	12		12	12		12	12	12	12	12	12
	3	12		12	12		12	10	10	10	10	10
	4 or more	12		12	12		12	10	10	10	10	10
Number	Total Input		Total Vent Height (Measured in Feet Above Draft Hood)
if Units		10		15	20		30	40	50	60	80	100
	Btuh x 1000
Combined				Manifold and Common Vent Diameter (in Inches)
2	1040	16		16	14		14	14	14	12	12	12
3	1560	20		18	18		16	16	14	14	14	14
4	2080	22		22	20		18	18	18	16	16	14
5	2600	26		24	22		20	20	18	18	18	18
6	3120	28		26	24		22	22	20	20	18	18
7	3640	30		28	26		24	24	22	22	20	20
8	4160	32		30	28		26	24	24	22	22	20

MODEL HW-610 BOILER

	Input: 610,000 Btuh							Draft Hood Outlet 12"
	Required Connector or					Smoke Pipe Diameter
	Connector		Total Vent Height (Measured in Feet Above Draft Hood)
		10		15	20		30	40	50	60	80	100
	Rise in Feet
						Connector Diameter (in Inches)
	1	16		14	14		14	14	14	14	14	14
	2	14		14	14		14	14	12	12	12	12
	3	14		14	12		12	12	12	12	12	12
	4 or more	12		12	12		12	12	12	12	12	12
Number	Total Input		Total Vent Height (Measured in Feet Above Draft Hood)
if Units		10		15	20		30	40	50	60	80	100
	Btuh x 1000
Combined				Manifold and Common Vent Diameter (in Inches)
2	1220	18		18	16		16	14	14	14	14	14
3	1830	22		20	20		18	18	16	16	16	14
4	2440	26		24	22		20	20	18	18	18	16
5	3050	28		26	26		24	22	22	20	20	18
6	3660	32		28	28		26	24	24	22	22	20
7	4270	34		32	30		28	26	24	24	22	22
8	4880	36		34	32		30	28	26	26	24	24
9	5490	38		36	34		30	30	28	28	26	24
10	6100	40		38	36		32	30	30	28	26	26
11	6710	42		38	38		34	32	30	28	28	26
12	7320	44		42	38		36	34	32	32	30	28
		MODEL HW-670 BOILER
Input: 660,000 or 670,000 Btuh								Draft Hood Outlet 12"
	Required Connector or					Smoke Pipe Diameter
	Connector		Total Vent Height (Measured in Feet Above Draft Hood)
		10		15	20		30	40	50	60	80	100
	Rise in Feet
						Connector Diameter (in Inches)
	1	16		14	14		14	14	14	14	14	14
	2	14		14	14		14	14	12	12	12	12
	3	14		14	12		12	12	12	12	12	12
	4 or more	12		12	12		12	12	12	12	12	12
Number	Total Input		Total Vent Height (Measured in Feet Above Draft Hood)
if Units		10		15	20		30	40	50	60	80	100
	Btuh x 1000
Combined				Manifold and Common Vent Diameter (in Inches)
2	1220	18		18	16		16	14	14	14	14	14
3	1830	22		20	20		18	18	16	16	16	14
4	2440	26		24	22		20	20	18	18	18	16
5	3050	28		26	26		24	22	22	20	20	18
6	3660	32		28	28		26	24	24	22	22	20
7	4270	34		32	30		28	26	24	24	22	22
8	4880	36		34	32		30	28	26	26	24	24
9	5490	38		36	34		30	30	28	28	26	24
10	6100	40		38	36		32	30	30	28	26	26
11	6710	42		38	38		34	32	30	28	28	26
12	7320	46		44	40		38	36	34	34	32	30

Known: (5) model HW-610 boilers. (See illustration). Connector rise - 2' (Note 1' is minimum). Total vent height 30'.

Problem: Determine diameter of connector, manifold and common vent.

Procedure: Enter the top of the HW-610 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.

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