The Valve,check, cataloged under National Stock Number 4820-00-850-3201, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 13 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-00-850-3201 |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Flow Control Device | DISK |
| Connection Style | SOCKET (TUBE) ALL ENDS |
| Mounting Position | HORIZONTAL |
| Connection Type | UNTHREADED INTERNAL TUBE ALL ENDS |
| Style Designator | STRAIGHT THRU |
| Nominal Outside Diameter Tube Accommodated | 2.000 INCHES ALL ENDS IN |
| Operating Pressure | 125.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM FIRST RESPONSE LBS |
| Operating Pressure | 225.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SECOND RESPONSE LBS |
| Disk Loading Method | SPRING |
| Media for Which Designed | WATER-OIL-GAS SECOND RESPONSE |
| Media for Which Designed | STEAM FIRST RESPONSE |
| Material | COPPER ALLOY OVERALL |
| 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 |
|---|---|
| 1B912-2IN | 3/9 Design control — primary reference Hammond Valve Corp |
| M10109 | 5/9 Secondary reference Mueller Brass Co. |
NSN 4820-00-850-3201 is a Valve,check, classified under FSC 4820, Valves, Nonpowered. Status: active.
2 possible matches (shared part number, not a government interchangeability claim): 6625-01-278-3550, 2530-01-664-7870. Verify interchangeability with system specifications before substitution.
Key specifications for 4820-00-850-3201: Flow Control Device: DISK; Connection Style: SOCKET (TUBE) ALL ENDS; Mounting Position: HORIZONTAL; Connection Type: UNTHREADED INTERNAL TUBE ALL ENDS. 13 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.