Rinnai RU80i Installation And Operation Manual page 21

OPTION 2:
Maximum Equivalent Vent Length Tables:
Determine the number of 90 degree elbows in the vent system. (two 45 degree elbows count as one 90 degree elbow.)
Refer to the tables below to find the maximum vent length based on the number of elbows and termination style.
Total Equivalent Vent Length (Intake/outlet) for Twin Pipe 3" PVC/CPVC
Maximum Vent Length
Termination Type
Termination Equivalent Length in feet
(meters) (Already factored into the straight
pipe lengths below)
# of 90° Elbows (each: 5 equivalent feet)
0
1
2
3
4
5
6
Total Equivalent Vent Length (Intake/outlet) for Twin Pipe 4" PVC/CPVC
Maximum Vent Length
Termination Type
Termination Equivalent Length in feet
(meters) (Already factored into the straight
pipe lengths below)
# of 90° Elbows (each: 5 equivalent feet)
0
1
2
3
4
5
6
**Dip switch one (bank of eight - TAN COLORED) off for lenths greater than or equal to 21 feet
Maximum vent lengths are specific to the fuel type of the tankless water heater. It is imperative when
performing equivalent vent length calculations, that the gas type be taken into consideration.
Natural Gas Units
65 Feet
IPEX Concentric Snorkel
Vent Kit Termination
20 (6.1) 10 (3.0)
Max. straight pipe vent length in feet (meters)
45 (13.7) ** 55 (16.8) **
40 (12.2) ** 50 (15.2) **
35 (10.7) ** 45 (13.7) **
30 (9.1) ** 40 (12.2) **
25 (7.6) ** 35 (10.7) **
20 (6.1) ** 30 (9.1) **
15 (4.6) ** 25 (7.6) **
Natural Gas Units
100 Feet
IPEX Concentric Snorkel
Vent Kit Termination
20 (6.1) 10 (3.0)
Max. straight pipe vent length in feet (meters)
80 (24.4) ** 90 (27.4) **
75 (22.9) ** 85 (25.9) **
70 (21.3) ** 80 (24.4) **
65 (19.8) ** 75 (22.9) **
60 (18.3) ** 70 (21.3) **
55 (16.8) ** 65 (19.8) **
50 (15.2) ** 60 (18.3) **
ATTENTION
KB Series Manual
Side Wall Tee Low Profile
Termination Termination
5 (1.5) 5 (1.5)
60 (18.3) ** 60 (18.3) **
55 (16.8) ** 55 (16.8) **
50 (15.2) ** 50 (15.2) **
45 (13.7) ** 45 (13.7) **
40 (12.2) ** 40 (12.2) **
35 (10.7) ** 35 (10.7) **
30 (9.1) ** 30 (9.1) **
Side Wall Tee Low Profile
Termination Termination
5 (1.5) 5 (1.5)
95 (29.0) ** 95 (29.0) **
90 (27.4) ** 90 (27.4) **
85 (25.9) ** 85 (25.9) **
80 (24.4) ** 80 (24.4) **
75 (22.9) ** 75 (22.9) **
70 (21.3) ** 70 (21.3) **
65 (19.8) ** 65 (19.8) **
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