Bryant 351DAS warranty COMBUSTION-AIR and Vent Piping, Maximum Allowable Pipe Length FT

COMBUSTION-AIR AND VENT PIPING

MAXIMUM ALLOWABLE PIPE LENGTH (FT)

ALTITUDE						NUMBER OF 90° ELBOWS
ABOVE SEA			PIPE DIA
LEVEL (FT)	UNIT SIZE	TERMINATION TYPE	(IN.)*	1	2		3	4	5	6
	036080		1-1/2	10	NA		NA	NA	NA	NA
0 to 2000	048080	2 Pipe or 2-In. Concentric	2	55	50		35	30	30	20
	060080		2-1/2	70	70		70	70	70	70
	036080		2	49	44		30	25	25	15
2001 to 3000	048080	2 Pipe or 2-In. Concentric
			2-1/2	70	70		70	70	70	70
	060080
	036080		2	46	41		28	23	22	13
3001 to 4000	048080	2 Pipe or 2-In. Concentric	2-/12	70	70		70	70	70	70
	060080
	036080		2	44	39		26	21	20	11
4001 to 5000†	048080	2 Pipe or 2-in Concentric
			2-1/2	70	70		70	70	70	70
	060080
	036080		2	41	36		23	18	17	8
5001 to 6000†	048080	2 Pipe or 2-In. Concentric
			2-1/2	70	70		70	70	70	70
	060080
	036080		2	38	33		21	16	15	6
6001 to 7000†	048080	2 Pipe or 2-In. Concentric	2-1/2	70	70		68	67	66	64
	060080
	036080		2	36	31		19	14	12	NA
7001 to 8000†	048080	2 Pipe or 2-In. Concentric
			2-1/2	66	65		63	62	60	59
	060080
	036080		2	33	28		17	12	10	NA
8001 to 9000†	048080	2 Pipe or 2-In. Concentric
			2-1/2	62	60		58	56	55	53
	060080
9001 to	036080		2	30	25		14	9	7	NA
10,000†	048080	2 Pipe or 2-In. Concentric	2-1/2	57	55		53	51	49	47
	060080

*Disk usage—Unless otherwise specified, use perforated disk assembly (factory-supplied in loose parts bag).

†Vent sizing for Canadian installations over 4500 ft (1370m) 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.Size both the combustion-air and vent pipe independently, then use the larger diameter for both pipes.

3.Assume two 45° elbows equal one 90° elbow. Long radius elbows are desirable and may be required in some cases.

4.Elbows and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.

5.The minimum pipe length is 5 ft for all applications.

MAXIMUM ALLOWABLE EXPOSED VENT PIPE LENGTH (FT) WITH AND WITHOUT INSULATION

IN WINTER DESIGN TEMPERATURE AMBIENT*

	WINTER DESIGN	MAX PIPE
	TEMPERATURE	DIAMETER	WITHOUT	WITH 3/8-IN. OR
UNIT SIZE	(°F)	(IN.)	INSULATION	THICKER INSULATION†
036080	20	2-1/2	70	70
048080	0	2-1/2	47	70
060080
	–20	2-1/2	28	70

*Pipe length (ft) specified for maximum vent pipe lengths located in unconditioned spaces. Vent pipes located in unconditioned space cannot exceed the

total allowable pipe length as specified in Maximum Allowable Pipe Length table.

† Insulation thickness based on R value of 3.5 per in.

—5—