A.O. Smith Residential Power Vent Gas Water Heaters with Hot Surface Ignition Venting cont’d

Installing the New Water Heater (cont’d)

Venting (cont’d)

VENTING THROUGH AN OUTSIDE WALL (cont’d)

40 AND 50 GALLON 40,000 BTU/HR MODELS (3″ VENT)

SEE CHART BELOW FOR MAX. LENGTH

		4′ MIN.
151⁄2″ MIN.	MIN. RISE 1⁄8″
		14″ MIN.
	PER FIVE FEET

2.The total vertical and horizontal vent run cannot exceed the maximum length with the number of 90° elbows as specified in the tables below. If more elbows are required the venting distance must be reduced 5 feet for every 90˚ elbow:

75 GALLON 70,000 and 75,000 BTU/HR, 50 GALLON 52,500, 55,000 and 62,500 BTU/HR and 40 GALLON 50,000 BTU/HR MODELS ONLY

3″ DIA. VENT	NUMBER OF
MAX. LENGTH (FT.)	90° ELBOWS*
70	1
65	2
60	3
55	4
50	5
45	6

75 GALLON 70,000 and 75,000 BTU/HR, 50 GALLON 52,500,

55,000 and 62,500 BTU/HR and 40 GALLON 50,000 BTU/HR MODELS ONLY – OPTIONAL 4″ VENT PIPING

4″ DIA. VENT	NUMBER OF
MAX. LENGTH (FT.)	90° ELBOWS*
110	1
105	2
100	3
95	4
90	5
85	6

ALL 40 and 50 GALLON 40,000 BTU/HR MODELS ONLY

3″ DIA. VENT	NUMBER OF
MAX. LENGTH (FT.)	90° ELBOWS*
115	1
110	2
105	3
100	4
95	5
90	6

ALL 40 and 50 GALLON 40,000 BTU/HR MODELS —

OPTIONAL 2″ VENT PIPING

2″ DIA. VENT	NUMBER OF
MAX. LENGTH (FT.)	90° ELBOWS*
50	1
45	2
40	3
35	4
30	5
25	6

*NOTE: Two 45° elbows are equivalent to one 90° elbow. One 90° elbow equals 5 feet of equivalent vent length.

95’ MAX.

MIN. RISE 1⁄8″

PER FIVE FEET

20’

(EXAMPLE) ONE ELBOW EXAMPLE

3″ VENT PIPE

40 GALLON

40,000 BTU/HR

MODEL EXAMPLE

3.Minimum vent length for all 40,000 BTU/HR input models is 4 feet and 16 inches for all other models.

VENTING THROUGH AN OUTSIDE WALL WITH LOW GROUND CLEARANCE

1.When the vent piping cannot pass through an outside wall at a height greater than or equal to 12″ above the ground (or above snow accumulation level), then the installation can be modified as shown below.

12″ MIN. ABOVE

GROUND OR SNOW

ACCUMULATION LEVEL

18