Maximum Vent Length - Rinnai RL75I Operation And Installation Manual

Maximum Vent Length

1. Determine the number of 90 degree elbows in the vent system. (Two 45 degree elbows count as one 90
degree elbow. On the R98 models each one foot of semi rigid flex duct used in the air intake length is
equivalent to one 90 degree elbow.)
2. Refer to the table to find the maximum vent length based on the number of elbows.
3. Follow the applicable note.
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.
0
41 ft 1
(12.5 m)
1 If the length is greater than 21 ft (6.4 m) then move
switch no. 1 (SW1) to OFF.
2 If the length is greater than 15 ft (4.6 m) then move
switch no. 1 (SW1) to OFF.
3 If the length is greater than 9 ft (2.7 m) then move
switch no. 1 (SW1) to OFF.
4 Move switch no. 1 (SW1) to OFF.
NOTICE
If you have a longer vent length, switch no. 1 is required to be in the OFF position. This ensures the water
heater will run properly. Blocked flue error codes and shutdowns may result if switch no. 1 is not in the correct
position. On the RL94i, the maximum water flow capacity will be reduced by about 10% when switch no. 1 is
OFF.
Number of 90° Elbows
1 2
35 ft 2 29 ft 3
(10.7 m) (8.8 m)
VB Series Indoor LS Manual
3 4
23 ft 4 17 ft 4
(7.0 m) (5.2 m)
Notes 1234
5 6
11 ft 4 5 ft 4
(3.4 m) (1.5 m)
Switch No.
ON
O
1
F
2
F
3
4
5
6
7
8
27