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16
Installation and Maintenance
Model 121 Regulators
2
1
3
4
5
25
21
22
23
25
27
29
33
35
32
37
38
19a
19
18
17
16b
16a
15
15a
14
a
b
c
d
12
13
2a
8
7
9
10
21a
a
b
c
d
f
h
11
45
26
28
32
34
24
1" NPT Vent
connection
3" 121 as shown.
4" uses a spacer, approx.
1" O.D. x 3/4" I.D. x 3/16" thick
2
1
3
9
45
21
22
23
24
25
26
27 28
13
a
b
c
d
f
h
11
21a
1/4" NPT
Control
line connection
2
1
3
26
5
4
21a
h
f
d
c
b
a
11
13
a
b
c
d
12
14
15a
15
16a
16b
17
18
19
19a
38
37
32
35
21
45
22
23
24
25
26
27
28
29
32
33
34
2a
8
7
9
10
1/4" NPT
Control line
connection
2a
1
3
9
45
21
a
b
c
d
f
h
11
21a
22
23
24
28
27
26
25
1" NPT Vent
connection
1/4" NPT
Control line
connection
3" – 4" Standard
3" – 4"
Back Pressure
Pipe Sizes
(inlet x outlet)
Flanged ANSI
125 lb. FF
3" x 3"
4" x 4"