PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

K 521Parts Kit,pilot Control Valve

Waterous Company · NSN 4820-01-272-7625 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-01-272-7625 — this item is cataloged by the U.S. Government under National Stock Number 4820-01-272-7625. Primary manufacturer part number: K 521.
Features
  • Parts Kit,pilot Control Valve — FSC 4820
  • Nonsupply Items and Quantities: GROOVE PIN 2; O-RING 3; SPIRAL PIN 1; 4-WAY VALVE 1; 4-WAY VALVE SPRING 1; GASKET 1; STRAINER ASSY 1
  • Component Quantity: 10
  • 2 verified cross-references
  • Primary manufacturer: Waterous Company
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
General Description

The Parts Kit,pilot Control Valve, cataloged under National Stock Number 4820-01-272-7625, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Waterous Company. Government technical data includes 2 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 2 commercial cross-references from 1 manufacturer, enabling identification through both NSN and commercial part number lookups. 1 verified substitute exists in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4820-01-272-7625
Primary Part NumberK 521
Item NameParts Kit,pilot Control Valve
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerWaterous Company
StatusACTIVE
Nonsupply Items and QuantitiesGROOVE PIN 2; O-RING 3; SPIRAL PIN 1; 4-WAY VALVE 1; 4-WAY VALVE SPRING 1; GASKET 1; STRAINER ASSY 1
Component Quantity10
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 1
3460-00-491-0224K521 INTERCHANGEABLE
Wheel,abrasive
Sioux Tools Inc
Cross-Reference Index
Part NumberManufacturer
K 521 PRIMARY Waterous Company (USA)
521 Waterous Company (USA)
Related Parts
3460-00-491-0224INTERCHANGEABLE
WHEEL,ABRASIVE
K521

Frequently Asked Questions

What is NSN 4820-01-272-7625?

NSN 4820-01-272-7625 is a Parts Kit,pilot Control Valve, manufactured by Waterous Company, classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-01-272-7625?

NSN 4820-01-272-7625 has 2 cross-referenced part numbers: K 521 (Waterous Company), 521 (Waterous Company).

What NSN replaces 4820-01-272-7625?

There is 1 known substitute for 4820-01-272-7625: 3460-00-491-0224. Verify interchangeability with system specifications before substitution.

What are the specifications of K 521?

Key specifications for K 521: Nonsupply Items and Quantities: GROOVE PIN 2; O-RING 3; SPIRAL PIN 1; 4-WAY VALVE 1; 4-WAY VALVE SPRING 1; GASKET 1; STRAINER ASSY 1; Component Quantity: 10. 2 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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