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13
Installation and Maintenance
Model 121 Regulators
Condensed Parts List 1-1/2", 2" and 2-1/2"
Illustration
Description
Part
Number
Number
1
Seal Cap
143-16-005-00
1a
Seal Cap
121-10-005-52
2
Tetraseal (or O-Ring) 2-1/4" x 2-3/8" 905241
2a
Tetraseal (or O-Ring) 1-1/2" x 1-5/8" 906534
3
Adjustment Spring Button
143-16-009-00
3a
Spring Adjusting Screw
906537
4
Hex Steel Nut
921005
5
Housing Cover
121-10-005-51
7a
Top Spring Button
121-10-009-51
7b
Thrust Bearing, stainless ball,
930510
3/8" diameter
9
Spring, see table “Spring Ranges”
121-12 Diaphragm Assembly
121-16-550-51
(3-1/2" w.c. to 2 psi outlet pressure)
11a Elastic Stop Nut 52-NTE-066
908561
11b Bottom Spring Button
121-10-022-50
11
11c Diaphragm Pan
121-16-017-50
11d Molded Diaphragm, Buna-N
121-16-150-53
11d Diaphragm, Viton
121-16-150-55
11f Seal Washer
121-10-178-50
11h Diaphragm Stud, stainless steel 121-16-058-52
121-8 Standard Diaphragm
Assembly
121-10-551-52
(1 psi to 4-1/4 psi outlet pressure)
11a Elastic Stop Nut 29-NE-066
903955
11
11b Bottom Spring Button
121-10-022-50
11c Diaphragm Pan
121-10-017-50
11d Diaphragm, Buna-N
121-10-150-50
11d Diaphragm, Viton
121-10-150-52
11f Seal Washer
121-10-178-50
11h Diaphragm Stud, stainless steel 091-16-058-02
121-8 HP High Pressure
Diaphragm Assembly
121-10-550-55
(3 psi to 10 psi outlet pressure)
11a Elastic Stop Nut 29-NE-066
903955
11b Diaphragm Plate
121-10-022-53
11
11c Diaphragm Pan
121-10-017-50
11d Diaphragm, Buna-N
121-10-150-50
11d Diaphragm, Viton
121-10-150-52
11e Upper Plate
121-10-022-52
11f Seal Washer
121-10-178-50
11g Lower Plate
121-10-079-52
11h Diaphragm Stud, stainless steel 091-16-058-02
121 Seal Diaph Assembly, Buna-N
121-16-564-51
121 Seal Diaph Assembly, Viton
121-16-564-52
12a Piston
121-16-053-51
12b Seal Diaphragm, Buna-N
121-16-364-50
12
12b Seal Diaphragm, Viton
121-16-364-51
12c Plate
121-16-010-53
12d Stem, stainless steel
121-16-016-53
12e Retainer
121-16-016-00
12f V-Port Wings
121-16-012-52
O-Ring, Buna-N 3/8" x 1/2"
934007
13
O-Ring, Viton 3/8" x 1/2"
902418
14
Wave Washer
905479
Condensed Parts List 1-1/2", 2" and 2-1/2"
Illustration
Description
Part
Number
Number
15
Molded Valve, Buna-N (45-50 Duro) 121-16-311-50
Molded Valve, Viton-A (65-75 Duro) 121-16-311-51
16a
Retaining Ring
904447
16b
Valve Holder, split (pair required)
121-16-130-51
stainless steel
18
Tetraseal (or O-Ring)
904207
2-1/2" x 2-11/16"
19
Orifice, 2-5/32" dia., stainless steel
121-16-023-51
Orifice, 2-5/32" dia., stainless steel
121-16-023-52
19a
Retaining Ring, stainless
904656
26
Gasket
121-16-063-51
29a
Copper Washer
121-16-178-51
30
O-Ring, 3-1/8" x 3-1/2"
934041
32
Tetraseal (or O-Ring) 3-1/4" x 3-1/2" 904078
33
Seal Diaphragm Ring
121-16-008-50
34
Gasket
121-16-104-50
45
Travel Indicator
Contact Sensus
Repair Kits, consisting of Buna-N Main and Seal
Diaphragms, Buna-N Molded Valve plus Wave
Washer and Retaining Ring, Buna-N O-Rings,
46
Tetraseals and Gaskets:
For 121-12
121-16-598-50
For 121-8
121-86-598-50
For 121-8 HP
121-86-598-51
For Back Pressure Models
Item 12d above, Stem,
12
Stainless Steel –
121-16-016-55
substitute Stem, Back Pressure
Item 14 above,
14
Wave Washer – substitute
Poly-U Disk
121-16-102-52
Retainer
121-16-103-51
Item 46 above,
Repair Kits – substitute
46
For 121-12 Back Pressure
121-16-598-52
For 121-8 Back Pressure
121-86-598-54
For 121-8 HP Back Pressure
121-86-598-55
Add item 47
47
Valve, Seal Diaphragm and
121-16-511-51
Stem Assembly