The Valve,safety Relief, cataloged under National Stock Number 4820-00-541-7659, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 18 specifications, cited from the U.S. Government catalog. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-541-7659 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Surface Treatment Document and Classification | MIL-A-8625,TY 2 MIL SPEC SINGLE TREATMENT RESPONSE LOCATION NOT OTHERWISE SPECIFIED |
| Connection Style | GASKET SEAL(BOSS) FIRST END |
| Connection Type | THREADED INTERNAL BOSS FIRST END |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES FIRST END IN |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Adjustable Pressure Range | +2300.0 TO 3850.0 POUNDS PER SQUARE INCH LBS |
| Features Provided | PRESSURE TIGHT OUTLET SIDE |
| Bonnet Type | PACKING RETAINING |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.437 INCHES FIRST END IN |
| Disk Loading Method | SPRING |
| Surface Treatment | ANODIZE LOCATION NOT OTHERWISE SPECIFIED |
| Media for Which Designed | OIL, HYDRAULIC SINGLE RESPONSE |
| Thread Class | 3B FIRST END |
| Thread Quantity Per Inch | 20 FIRST END |
| Thread Series Designator | UNF FIRST END |
| Valve Operation Method | AUTOMATIC |
| 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 |
|---|---|
| 4381026-527 | 5/2 Secondary reference U.S. Government activity |
| A40154A3650 | 3/2 Design control — primary reference U.S. Government activity |
| A40154A | 3/2 Design control — primary reference U.S. Government activity |
| 7545912-507 | 7/2 Vendor item drawing reference The Boeing Company |
| 7545912-507 | 5/2 Secondary reference U.S. Government activity |
| 4381026-527 | 5/9 Secondary reference The Boeing Company |
NSN 4820-00-541-7659 is a Valve,safety Relief, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-541-7659: Flow Control Device: POPPET; Surface Treatment Document and Classification: MIL-A-8625,TY 2 MIL SPEC SINGLE TREATMENT RESPONSE LOCATION NOT OTHERWISE SPECIFIED; Connection Style: GASKET SEAL(BOSS) FIRST END; Connection Type: THREADED INTERNAL BOSS FIRST END. 18 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.