10
UGTC Series 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.
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.
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
Maximum vent length
(concentric venting)
0
41 ft (12.5 m)
1
35 ft (10.7 m)
2
29 ft (8.8 m)
3
23 ft (7.0 m)
4
17 ft (5.2 m)
5
11 ft (3.4 m)
6
5 ft (1.5 m)
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.
NOTICE
Vent length using short radius elbow
Number of
90° Short
Radius
Elbows
Maximum
Straight Vent
Length
Switch #1 in the tan
DIP switches
If length is greater
than:
0
42 ft (12.80 m)
18 ft (5.49 m) move
1
27 ft (8.23 m)
3 ft (0.91 m) move
2
12 ft (3.66 m)
move switch #1 to OFF
for any length
Number of
90° Long
Radius
Elbows
Maximum
Straight Vent
Length
Switch #1 in the tan
DIP switches
If length is greater
than:
0
45 ft (13.72 m)
21 ft (6.40 m) move
1
39 ft (11.89 m)
15 ft (4.57 m) move
2
33 ft (10.06 m)
9 ft (2.74 m) move
3
27 ft (8.23 m)
3 ft (0.91 m) move
4
21 ft (6.40 m)
move switch #1 to
OFF for any length
5
15 ft (4.57 m)
6
9 ft (2.74 m)
7
3 ft (0.91 m)
Vent length using long radius elbow
Maximum vent length for Centrotherm 2 Pipe
InnoFlue Vent System (single wall SW, 3 inch
diameter)
