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Watts
Plumbing

Model # 1789 Official Watts 3/4" water pressure reducing valve

Here are the diagrams and repair parts for Official Watts 1789 3/4" water pressure reducing valve, as well as links to manuals and error code tables, if available.

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Not all parts are shown on the diagrams—those parts are labeled NI, for “not illustrated”.

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Error Codes

Model diagram and schematic

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Showing 10 of 45 parts  |
Union Nut 35C140
#21C

Replacement parts diagram

Union nut

Part #35C140

The manufacturer no longer makes this part, and there's no substitute part

Service Kit 5C

#NI

All parts diagram

Service kit

Part #5C

The manufacturer no longer makes this part, and there's no substitute part

Lock Nut 30AL51
#7

Replacement parts diagram

Lock nut

Part #30AL51

The manufacturer no longer makes this part, and there's no substitute part

Diagram 135A20
#10A

Replacement parts diagram

Diagram

Part #135A20

The manufacturer no longer makes this part, and there's no substitute part

675.4 (1/2") 56C8102
#22A

Replacement parts diagram

675.4 (1/2")

Part #56C8102

The manufacturer no longer makes this part, and there's no substitute part

Plate 135B66-M2
#9B

Replacement parts diagram

Plate

Part #135B66-M2

The manufacturer no longer makes this part, and there's no substitute part

Plug N36A2
#17A

Replacement parts diagram

Plug

Part #N36A2

The manufacturer no longer makes this part, and there's no substitute part

Gasket 1-1/16X1-1/4
#18B

Replacement parts diagram

Gasket

Part #1-1/16X1-1/4

The manufacturer no longer makes this part, and there's no substitute part

Union Tailpc 135B139
#23B

Replacement parts diagram

Union tailpc

Part #135B139

The manufacturer no longer makes this part, and there's no substitute part

Union Tailpc 135C139
#23C

Replacement parts diagram

Union tailpc

Part #135C139

The manufacturer no longer makes this part, and there's no substitute part

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