Lochinvar RPD-I-S User Manual page 12

Venting continued-
The minimum equivalent length for the exhaust portion of the vent is 7
feet. The maximum equivalent vent length for the exhaust is 60 feet for
3" diameter pipe (50 feet for the 75 gal.) and 100 feet for 4" diameter
pipe (90 feet for the 75 gal.). The intake portion of the vent must be
equal to or less than the vent length of the exhaust. The tables below
are provided for your quick reference, some installations may require a
greater number of elbows. When calculating equivalent vent length,
one 90º elbow is equivalent to 5 feet.
TABLE 1 - VENT CONNECTOR LENGTHS
FOR 3" (7.6 cm) DIAMETER VENT PIPE
# of Elbows
Terminating (excl. vent
Through the Wall
Through the Wall
Through the Wall
Through the Wall
Through the Roof
Through the Roof
Through the Roof
Through the Roof
TABLE 2 -VENT CONNECTOR LENGTHS
FOR 4" (10.2 cm) DIAMETER VENT PIPE
Terminating Elbows (excl.
vent term.)
Through the Wall
Through the Wall
Through the Wall
Through the Wall
Through the Wall
Through the Roof
Through the Roof
Through the Roof
Through the Roof
Through the Roof
IMPORTANT
Maximum straight
Length ft (m)
48, 65
term.)
gal.
1 55 (16.8)
2 50 (15.2)
3 45 (13.7)
4 40 (12.2)
0 60 (18.3)
1 55 (16.8)
2 50 (15.2)
3 45 (13.7)
Maximum straight
# of 90
Length ft (m)
48, 65 gal.
1 95 (29.0)
2 90 (27.4)
3 85 (25.9)
4 80 (24.4)
5 75 (22.9)
0 100 (30.5)
1 95 (29.0)
2 90 (27.4)
3 85 (25.9)
4 80 (24.4)
12
Minimum
straight
Length
75 gal.
ft (m)
45 (13.7) 2 (.6)
40 (12.2) 2 (.6)
35 (10.7) 2 (.6)
30 (9.1) 2 (.6)
50 (15.2) 7 (2.1)
45 (13.7) 7 (2.1)
40 (12.2) 7 (2.1)
35 (10.7) 7 (2.1)
Min
straight
Length
75 gal.
ft (m)
85 (25.9) 10 (3.1)
80 (24.4) 10 (3.1)
75 (22.9) 10 (3.1)
70 (21.3) 10 (3.1)
65 (19.8) 10 (3.1)
90 (27.4) 15 (4.6)
85 (25.9) 15 (4.6)
80 (24.4) 15 (4.6)
75 (22.9) 15 (4.6)
70 (21.3)
15 (4.6)
RPD-I-S Rev A