The Valve,restrictor Check, cataloged under National Stock Number 4820-00-485-7841, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems. Government technical data includes 26 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 4 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-485-7841 |
| Primary Part Number | A51H209-3 |
| Item Name | Valve,restrictor Check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END |
| Connection Style | GASKET SEAL (BOSS) FIRST END |
| Mounting Position | HORIZONTAL OR VERTICAL |
| Connection Type | THREADED INTERNAL BOSS FIRST END |
| Connection Type | THREADED EXTERNAL BOSS SECOND END |
| Style Designator | STRAIGHT THRU |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES FIRST END IN |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES SECOND END IN |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Aperture Diameter | 0.032 INCHES NOMINAL IN |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.437 INCHES FIRST END IN |
| Nominal Thread Size | 0.437 INCHES SECOND END IN |
| Maximum Operating Temp | 275.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Surface Treatment | ANODIZE |
| Thread Class | 3A SECOND END A |
| Thread Class | 3B FIRST END |
| Thread Quantity Per Inch | 20 FIRST END |
| Material | ALUMINUM ALLOY 518.0 BODY |
| Material | ALUMINUM ALLOY 518.0 SEAT |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) FIRST END |
| Thread Series Designator | UNF SECOND 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 |
| Part Number | Manufacturer |
|---|---|
| A51H209-3 | Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems (USA) |
| Reference | Meaning |
|---|---|
| 46130 | 3/2 Design control — primary reference U.S. Government activity |
| A51H209-3 | 5/9 Secondary reference Northrop Grumman Systems Corporation |
| A51H9209-3 | C/1 Advisory reference — outside the item-of-supply concept Northrop Grumman Systems Corporation |
NSN 4820-00-485-7841 is a Valve,restrictor Check, manufactured by Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-485-7841 has 1 manufacturer part number on file: A51H209-3 (Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems).
4 possible matches (shared part number, not a government interchangeability claim): 2520-00-857-2315, 5961-01-176-3396, 2925-01-340-5504. Verify interchangeability with system specifications before substitution.
Key specifications for A51H209-3: Flow Control Device: POPPET; Connection Style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END; Connection Style: GASKET SEAL (BOSS) FIRST END; Mounting Position: HORIZONTAL OR VERTICAL. 26 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.