The Valve,restrictor Check, cataloged under National Stock Number 4820-00-301-0256, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 27 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-301-0256 |
| Item Name | Valve,restrictor Check |
| 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 |
| Connection Style | FLARED (TUBE) FIRST END |
| Connection Style | BEVELED (TUBE) SECOND END |
| Mounting Position | HORIZONTAL OR VERTICAL |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Connection Type | BUTT WELD TUBE SECOND END |
| Style Designator | STRAIGHT THRU |
| Material Document and Classification | QQ-A-200/4, COMP 5083, TEMPER H111 FED SPEC SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | QQ-A-200/4, COMP 5083, TEMPER H111 FED SPEC SINGLE MATERIAL RESPONSE SEAT |
| Nominal Outside Diameter Tube Accommodated | 1.000 INCHES SECOND END IN |
| Operating Pressure | 60.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Aperture Diameter | 0.060 INCHES NOMINAL IN |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.562 INCHES FIRST END IN |
| Seat Angle | 37.0 DEGREES FIRST END |
| Maximum Operating Temp | -65.0 FAHRENHEIT FIRST RESPONSE DEGF |
| Maximum Operating Temp | 135.0 FAHRENHEIT SECOND RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Surface Treatment | ANODIZE |
| Media for Which Designed | FUEL/OIL, HYDROCARBON SINGLE RESPONSE |
| Thread Class | 3A FIRST END A |
| Material | ALUMINUM ALLOY SEAT |
| Material | ALUMINUM ALLOY BODY |
| Material | PLASTIC POLYAMIDE NYLON FLOW CONTROL DEVICE |
| 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 |
|---|---|
| 2700122 | 3/2 Design control — primary reference U.S. Government activity |
| 2700172 | 3/2 Design control — primary reference U.S. Government activity |
| 749986-103 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-301-0256 is a Valve,restrictor Check, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-301-0256: Flow Control Device: POPPET; Surface Treatment Document and Classification: MIL-A-8625,TY 2 MIL SPEC SINGLE TREATMENT RESPONSE; Connection Style: FLARED (TUBE) FIRST END; Connection Style: BEVELED (TUBE) SECOND END. 27 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.