Maximum Vent Length - Rinnai RU80i Installation And Operation Manual

Maximum vent length

Maximum vent length with concentric venting
1.Determine the number of 90 degree elbows in the
vent system. (Two 45 degree elbows count as
one 90 degree elbow.)
2.Refer to the table to find the maximum vent length
based on the number of elbows.
Natural Gas Units Only
Ubbink Concentric
(90° elbow is equivalent to 6 feet; 45° elbow is equivalent to 3 feet.)
Maximum Equivalent Vent Length 65 ft (19.8 m)
Maximum Vent Length in feet
# of 90° Elbows
0
1
2
3
4
5
6
Propane Units Only
Ubbink Concentric
(90° elbow is equivalent to 6 feet; 45° elbow is equivalent to 3 feet.)
Maximum Equivalent Vent Length 41 ft (12.5 m)
Maximum Vent Length in feet
# of 90° Elbows
0
1
2
3
4
5
6
3.Adjust switch No. 1 in the SW1 DIP switch (tan
switches) if required by the applicable note.
 If the length is greater than 21 ft (6.4 m) then
move switch No. 1 (SW1) to OFF.
 If the length is greater than 15 ft (4.6 m) then
move switch No. 1 (SW1) to OFF.
 If the length is greater than 9 ft (2.7 m) then move
switch No. 1 (SW1) to OFF.
 Move switch No. 1 (SW1) to OFF.
(meters)
1
65 (19.8)
2
59 (18.0)
3
53 (16.2)
4
47 (14.3)
4
41 (12.5)
4
35 (10.7)
4
29 (08.8)
(meters)
1
41 (12.5)
2
35 (10.7)
3
29 (8.8)
4
23 (7.0)
4
17 (5.2)
4
11 (3.4)
4
5 (1.5)
KB Series Manual
Example: If you have one elbow then your
maximum vent length is 35 feet (10.7 m).
If your actual length is greater than 15 ft
(4.6 m) then move switch no. 1 (SW1) to
OFF.
NOTICE
If you have a longer vent length (see above), switch
No. 1 is required to be in the OFF position. This
ensures the water heater will run properly. Blocked
flue diagnostic codes and shutdowns may result if
switch No. 1 is not in the correct position.
Maximum vent length for Centrotherm 2 Pipe
InnoFlue Vent System (single wall SW, 3 inch diameter)
Vent length using short radius elbow
(Intake is the short UV protected 90° elbow)
Number of
Maximum
90° Short
Straight Vent
Radius
Length
Elbows
0 41 ft (12.50 m)
1 26 ft (7.93 m)
2 11 ft (3.35 m)
Vent length using long radius elbow
(Intake is the long UV protected 90° elbow)
Number of
Maximum
90° Long
Straight Vent
Radius
Length
Elbows
0 41 ft (12.50 m)
1 35 ft (10.67 m)
2 29 ft (8.84 m)
3 23 ft (7.01m)
4 17 ft (5.18 m)
5 11 ft (3.35 m)
6 5 ft (1.52 m)
Switch #1 in the tan
DIP switches
If length is greater
18 ft (5.49 m) move
switch #1 to OFF
3 ft (0.91 m) move
switch #1 to OFF
move switch #1 to
OFF for any length
Switch #1 in the tan
DIP switches
If length is greater
21 ft (6.40 m) move
switch #1 to OFF
15 ft (4.57 m) move
switch #1 to OFF
9 ft (2.74 m) move
switch #1 to OFF
3 ft (0.91 m) move
switch #1 to OFF
move switch #1 to
OFF for any length
11