The Valve,safety Relief, cataloged under National Stock Number 4820-00-795-5476, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Eaton Aerospace Llc Dba Sterer Engineering Div M.c.aerospace. Government technical data includes 19 specifications, cited from the U.S. Government catalog. The record lists 2 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-795-5476 |
| Primary Part Number | MC1637-3800 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Eaton Aerospace Llc Dba Sterer Engineering Div M.c.aerospace |
| Status | ACTIVE |
| Flow Control Device | PISTON |
| Renewable Seat Ring Type | PRESSED-IN |
| Surface Treatment Document and Classification | MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE LOCATION NOT OTHERWISE SPECIFIED |
| Connection Style | FLARED (TUBE) FIRST END |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Style Designator | STRAIGHT THRU |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES FIRST END IN |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) NOMINAL POWER DRIVE LBS |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.437 INCHES FIRST END IN |
| Seat Angle | 37.0 DEGREES FIRST END |
| Maximum Operating Temp | 160.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Surface Treatment | ANODIZE LOCATION NOT OTHERWISE SPECIFIED |
| Thread Class | 3A FIRST END A |
| Test Data Document | 81349-MIL-E-5272 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.). |
| Thread Quantity Per Inch | 20 FIRST END |
| Thread Series Designator | UNF FIRST END |
| Valve Operation Method | AIR |
| 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 |
|---|---|
| MC1637-3800 PRIMARY | Eaton Aerospace Llc Dba Sterer Engineering Div M.c.aerospace (USA) |
| 134SCH120-1 | Northrop Grumman Systems Corporation (USA) |
| Reference | Meaning |
|---|---|
| 872096-3800 | 5/9 Secondary reference Kidde-Fenwal, Llc |
NSN 4820-00-795-5476 is a Valve,safety Relief, manufactured by Eaton Aerospace Llc Dba Sterer Engineering Div M.c.aerospace, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-795-5476 has 2 manufacturer part numbers on file: MC1637-3800 (Eaton Aerospace Llc Dba Sterer Engineering Div M.c.aerospace), 134SCH120-1 (Northrop Grumman Systems Corporation).
Key specifications for MC1637-3800: Flow Control Device: PISTON; Renewable Seat Ring Type: PRESSED-IN; Surface Treatment Document and Classification: MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE LOCATION NOT OTHERWISE SPECIFIED; Connection Style: FLARED (TUBE) FIRST END. 19 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.