The Valve,check, cataloged under National Stock Number 4820-00-957-6749, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 24 specifications, cited from the U.S. Government catalog. 5 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-957-6749 |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Renewable Seat Ring Type | PRESSED-IN |
| Nominal Pipe Size Accommodated | 0.500 INCHES SECOND END IN |
| Surface Treatment Document and Classification | MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE |
| Connection Style | FLARED (TUBE) FIRST END |
| Connection Style | GASKET SEAL (BOSS) SECOND END |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Connection Type | THREADED INTERNAL BOSS SECOND END |
| Nominal Outside Diameter Tube Accommodated | 0.500 INCHES FIRST END IN |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.750 INCHES SECOND END IN |
| Nominal Thread Size | 0.750 INCHES FIRST END IN |
| Seat Angle | 45.0 DEGREES SECOND END |
| Seat Angle | 37.0 DEGREES FIRST END |
| Disk Loading Method | SPRING |
| Surface Treatment | ANODIZE |
| Media for Which Designed | FUEL/OIL, HYDROCARBON SINGLE RESPONSE |
| Thread Class | 3A FIRST END A |
| Thread Class | 3B SECOND END |
| Thread Quantity Per Inch | 16 SECOND END |
| Thread Quantity Per Inch | 16 FIRST END |
| Thread Series Designator | UNF FIRST END |
| Thread Series Designator | UNF SECOND END |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| 8C163 | 3/2 Design control — primary reference U.S. Government activity |
| 3C4296 | 5/2 Secondary reference U.S. Government activity |
| 10384329 | 6/9 Informative reference only Nimikkeistokeskus Ncb Finland |
| 369A8326 | 5/9 Secondary reference Mcdonnell Douglas Helicopter Co Inc |
| 369A8326 | 7/2 Vendor item drawing reference The Boeing Company |
NSN 4820-00-957-6749 is a Valve,check, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-957-6749: Flow Control Device: POPPET; Renewable Seat Ring Type: PRESSED-IN; Nominal Pipe Size Accommodated: 0.500 INCHES SECOND END IN; Surface Treatment Document and Classification: MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE. 24 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.