18
18-HD66D1-4
Damper
Diameter
Damper
Diameter
Damper
Diameter
Damper
Diameter
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Damper
Diameter
Damper
Diameter
CFM
CFM
Damper
Diameter
Damper
Diameter
CFM
CFM
500
600
700
800
4"
9%
12%
16%
4"
7%
10%
13%
4"
6%
9%
11%
4"
6%
8%
10%
6"
19%
27%
35%
6"
16%
23%
29%
6"
14%
19%
25%
6"
12%
17%
22%
7"
26%
36%
46%
7"
22%
30%
38%
7"
19%
26%
33%
7"
16%
23%
29%
8"
34%
48%
62%
8"
29%
40%
52%
8"
25%
34%
44%
8"
22%
30%
39%
9"
44%
61%
79%
9"
36%
51%
66%
9"
31%
44%
56%
9"
27%
38%
49%
10"
54%
78%
98%
10"
45%
65%
82%
10"
39%
56%
70%
10"
34%
49%
61%
12"
79%
100%
100%
12"
66%
87%
117%
12"
56%
74%
100%
12"
49%
65%
88%
14"
100%
100%
100%
14"
87%
100%
100%
14"
74%
100%
100%
14"
65%
94%
100%
16"
100%
100%
100%
16"
100%
100%
100%
16"
99%
100%
100%
16"
86%
100%
100%
18"
100%
100%
100%
18"
100%
100%
100%
18"
100%
100%
100%
18"
100%
100%
100%
Damper
Diameter
Damper
Diameter
Damper
Diameter
Damper
Diameter
Damper
Diameter
CFM
CFM
Damper
Diameter
Damper
Diameter
Damper
Diameter
CFM
CFM
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
o
rm
a
l
Mo
re
A
gg
re
ss
iv
e
Damper
Diameter
Damper
Diameter
Damper
Diameter
CFM
CFM
Damper
Diameter
CFM
900
1000
1100
1200
4"
5%
7%
9%
4"
4%
6%
8%
4"
4%
5%
7%
4"
4%
5%
7%
6"
11%
15%
19%
6"
10%
14%
18%
6"
9%
12%
16%
6"
8%
11%
15%
7"
14%
20%
26%
7"
13%
18%
23%
7"
12%
16%
21%
7"
11%
15%
19%
8"
19%
27%
34%
8"
17%
24%
31%
8"
16%
22%
28%
8"
14%
20%
26%
9"
24%
34%
44%
9"
22%
31%
40%
9"
20%
28%
36%
9"
18%
25%
33%
10"
30%
43%
54%
10"
27%
39%
49%
10"
25%
35%
45%
10"
23%
33%
41%
12"
44%
58%
78%
12"
40%
52%
70%
12"
36%
47%
64%
12"
33%
43%
58%
14"
58%
84%
100%
14"
52%
76%
96%
14"
47%
69%
87%
14"
43%
63%
80%
16"
77%
100%
100%
16"
69%
98%
100%
16"
63%
89%
100%
16"
58%
81%
100%
18"
100%
100%
100%
18"
90%
100%
100%
18"
82%
100%
100%
18"
75%
100%
100%
Damper
Diameter
Damper
Diameter
Damper
Diameter
CFM
CFM
Damper
Diameter
Damper
Diameter
Damper
Diameter
CFM
Damper
Diameter
Damper
Diameter
CFM
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
CFM
Damper
Diameter
Damper
Diameter
CFM
CFM
Damper
Diameter
Damper
Diameter
1300
1400
1500
CFM
1600
4"
3%
5%
6%
4"
3%
4%
6%
4"
3%
4%
5%
4"
3%
4%
5%
6"
7%
10%
13%
6"
7%
10%
13%
6"
6%
9%
12%
6"
6%
8%
11%
7"
10%
14%
18%
7"
9%
13%
16%
7"
9%
12%
15%
7"
8%
11%
14%
8"
13%
18%
24%
8"
12%
17%
22%
8"
11%
16%
21%
8"
11%
15%
19%
9"
17%
23%
30%
9"
16%
22%
28%
9"
15%
20%
26%
9"
14%
19%
25%
10"
21%
30%
38%
10"
19%
28%
35%
10"
18%
26%
33%
10"
17%
24%
31%
12"
30%
40%
54%
12"
28%
37%
50%
12"
26%
35%
47%
12"
25%
33%
44%
14"
40%
58%
73%
14"
37%
54%
68%
14"
35%
50%
64%
14"
33%
47%
60%
16"
53%
75%
96%
16"
49%
70%
89%
16"
46%
65%
83%
16"
43%
61%
78%
18"
69%
96%
100%
18"
64%
89%
100%
18"
60%
83%
100%
18"
56%
78%
100%
Damper
Diameter
Damper
Diameter
Damper
Diameter
CFM
Damper
Diameter
Damper
Diameter
CFM
CFM
Damper
Diameter
Damper
Diameter
Damper
Diameter
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Le
ss
A
gg
re
ss
iv
e
N
or
m
al
Mo
re
A
gg
re
ss
iv
e
Damper
Diameter
Damper
Diameter
Damper
Diameter
CFM
CFM
cfm
Damper
Diameter
CFM
1800
1900
2000
2200
4"
2%
3%
4%
4"
2%
3%
4%
4"
2%
3%
4%
4"
2%
3%
4%
6"
5%
8%
10%
6"
5%
7%
9%
6"
5%
7%
9%
6"
4%
6%
8%
7"
7%
10%
13%
7"
7%
9%
12%
7"
7%
9%
12%
7"
6%
8%
10%
8"
10%
13%
17%
8"
9%
13%
16%
8"
9%
12%
16%
8"
8%
11%
14%
9"
12%
17%
22%
9"
11%
16%
21%
9"
11%
15%
20%
9"
10%
14%
18%
10"
15%
22%
27%
10"
14%
21%
26%
10"
14%
20%
25%
10"
12%
18%
22%
12"
22%
29%
39%
12"
21%
27%
37%
12"
20%
26%
35%
12"
18%
24%
32%
14"
29%
42%
53%
14"
27%
40%
50%
14"
26%
38%
48%
14"
24%
34%
43%
16"
38%
54%
69%
16"
36%
51%
66%
16"
35%
49%
63%
16"
31%
44%
57%
18"
50%
69%
89%
18"
47%
66%
84%
18"
45%
63%
80%
18"
41%
57%
73%
Damper
Diameter
Damper
Diameter
Damper
Diameter
CFM
CFM
cfm
Damper
Diameter
CFM
MANUAL ZONE SIZING
Auto Zone Sizing is the optimal way to determine the amount of air flow into each zone, but this process is not
mandatory. Zone sizes can be set manually using the following guidelines.
EXAMPLE (highlighted below):
A 2-zone, 3-ton AC system is configured to move 1200 CFM. Zone 1 has a
12” zone damper and Zone 2 has a 16” zone damper.
The Normal sizing strategy would set Zone 1 at 43% and Zone 2 at 81%. If Zone 1 had two dampers (6” and
10”) the zone size % should be added together (11% & 33%) and set to 44%.
