The Valve,check, cataloged under National Stock Number 4820-00-321-0909, 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24 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-321-0909 |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | FLARED (TUBE) ALL ENDS |
| Mounting Position | HORIZONTAL OR VERTICAL |
| Connection Type | THREADED EXTERNAL TUBE ALL ENDS |
| Style Designator | STRAIGHT THRU |
| Material Document and Classification | QQ-A-225/6 FED SPEC SINGLE MATERIAL RESPONSE BODY |
| Operating Pressure | 35.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.750 INCHES ALL ENDS IN |
| Seat Angle | 37.0 DEGREES ALL ENDS |
| Maximum Operating Temp | 135.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Surface Treatment | ANODIZE |
| Media for Which Designed | ETHYLENE GLYCOL FOURTH RESPONSE |
| Media for Which Designed | CARBON DIOXIDE THIRD RESPONSE |
| Media for Which Designed | FUEL/OIL, HYDROCARBON SECOND RESPONSE |
| Media for Which Designed | ALCOHOL, ETHYL FIFTH RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Thread Class | 3A ALL ENDS A |
| Thread Quantity Per Inch | 16 ALL ENDS |
| Material | ALUMINUM ALLOY 2024 BODY |
| Thread Series Designator | UNIFIED NATIONAL JOINT (UNJ) ALL ENDS |
| Opening Pressure Setting | 18.0 POUNDS PER SQUARE INCH LBS |
| 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 |
|---|---|
| 212-061-643-1 | 1/2 Source control — Government-approved source U.S. Government activity |
| 869A8TT018 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-321-0909 is a Valve,check, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-00-321-0909: Flow Control Device: POPPET; Connection Style: FLARED (TUBE) ALL ENDS; Mounting Position: HORIZONTAL OR VERTICAL; Connection Type: THREADED EXTERNAL TUBE ALL ENDS. 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.