The Valve,bleeder,hydraulic System, cataloged under National Stock Number 4820-01-121-0917, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Bae Systems Surface Ships Limited. Government technical data includes 14 specifications, cited from the U.S. Government catalog. The record lists 4 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-121-0917 |
| Primary Part Number | HT2804 REF. SD2 1143 |
| Item Name | Valve,bleeder,hydraulic System |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Bae Systems Surface Ships Limited |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | PLAIN (PIPE) ALL ENDS |
| Connection Type | THREADED EXTERNAL PIPE ALL ENDS |
| Style Designator | ANGLE |
| Operating Pressure | 4000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.250 INCHES ALL ENDS IN |
| Maximum Operating Temp | 600.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Media for Which Designed | WATER-OIL-GAS SECOND RESPONSE |
| Media for Which Designed | AIR FIRST RESPONSE |
| Material | STEEL COMP 316 BODY |
| Material | STEEL COMP 316 FLOW CONTROL DEVICE |
| Thread Series Designator | NPT ALL ENDS |
| Valve Operation Method | MANUAL |
| 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 |
|---|---|
| HT2804 REF. SD2 1143 | Bae Systems Surface Ships Limited (GBR) |
| 1HVA-AA-0000-N0008 | Bae Systems Electronics Limited Div Underwater Systems Division (GBR) |
| 25790386 | Bae Systems Integrated System Technologies Ltd (GBR) |
| CV0427-001 | Northrop Grumman Corp Electronic Systems Defensive System Div (USA) |
| Reference | Meaning |
|---|---|
| SS4P4M | 3/9 Design control — primary reference Nupro Co |
NSN 4820-01-121-0917 is a Valve,bleeder,hydraulic System, manufactured by Bae Systems Surface Ships Limited, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-121-0917 has 4 manufacturer part numbers on file: HT2804 REF. SD2 1143 (Bae Systems Surface Ships Limited), 1HVA-AA-0000-N0008 (Bae Systems Electronics Limited Div Underwater Systems Division), 25790386 (Bae Systems Integrated System Technologies Ltd), CV0427-001 (Northrop Grumman Corp Electronic Systems Defensive System Div).
3 possible matches (shared part number, not a government interchangeability claim): 4820-01-150-1983, 4820-01-232-5431, 4820-01-330-4407. Verify interchangeability with system specifications before substitution.
Key specifications for HT2804 REF. SD2 1143: Flow Control Device: POPPET; Connection Style: PLAIN (PIPE) ALL ENDS; Connection Type: THREADED EXTERNAL PIPE ALL ENDS; Style Designator: ANGLE. 14 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.