Lennox International Inc Elite Series Gas Furnace Attic or Crawl Space For Intake Air in Feet

TABLE 6

Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated

Attic or Crawl Space For Intake Air in Feet

NOTE - Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total. Both Intake and Exhaust must be same pipe size.

NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.

Standard Termination at Elevation 0 - 4500 ft

Number Of			2” Pipe					2-1/2” Pipe						3” Pipe
			Model						Model					Model
90° Elbows
Used
	045	070	090	110	135	045	070		090	110	135	045	070	090	110	135
1	71	56	34	14		100	100		78	43		118	117	98	98	94
2	66	51	29	9		95	95		73	38		113	112	93	93	89
3	61	46	24	4		90	90		68	33		108	107	88	88	84
4	56	41	19			85	85		63	28		103	102	83	83	79
5	51	36	14			80	80		58	23		98	97	78	78	74
					n/a						n/a
6	46	31	9			85	75		63	18		93	92	73	73	69
7	41	26	4	n/a		70	70		48	13		88	87	68	68	64
8	36	21				65	65		43	8		83	82	63	63	59
9	31	16	n/a			60	60		38	3		78	77	58	58	54
10	26	11				55	55		33	n/a		73	72	53	53	49
				Standard Termination Elevation 4500 - 10,000 ft
Number Of			2” Pipe					2-1/2” Pipe						3” Pipe
			Model						Model					Model
90° Elbows
Used
	045	070	090	110	135	045	070		090	110	135	045	070	090	110	135
1	71	56	34			100	100		78	43		118	117	98	98	94
2	66	51	29			95	95		73	38		113	112	93	93	89
3	61	46	24			90	90		68	33		108	107	88	88	84
4	56	41	19			85	85		63	28		103	102	83	83	79
5	51	36	14			80	80		58	23		98	97	78	78	74
				n/a	n/a						n/a
6	46	31	9			85	85		53	18		93	92	73	73	69
7	41	26	4			70	70		48	13		88	87	68	68	64
8	36	21				65	65		43	8		83	82	63	63	59
9	31	16	n/a			60	60		38	3		78	77	58	58	54
10	26	11				55	55		33	n/a		73	72	53	53	49

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