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.

Number of 90° Elbows

0

1

2

3

4

5

6

 

 

 

 

 

 

 

41 ft 1

35 ft 2

29 ft 3

23 ft 4

17 ft 4

11 ft 4

5 ft 4

(12.5 m)

(10.7 m)

(8.8 m)

(7.0 m)

(5.2 m)

(3.4 m)

(1.5 m)

 

 

 

 

 

 

 

1If the length is greater than 21 ft (6.4 m) then move

switch no. 1 (SW1) to OFF.

Notes 1234

 

2If the length is greater than 15 ft (4.6 m) then move switch no. 1 (SW1) to OFF.

3If the length is greater than 9 ft (2.7 m) then move switch no. 1 (SW1) to OFF.

4Move switch no. 1 (SW1) to OFF.

Switch No.

ON

O1

F

F 2

3

4

5

6

7

8

VB Series Indoor LS Manual

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Rinnai RL75I, RL94I installation manual Maximum Vent Length