The Valve,safety Relief, cataloged under National Stock Number 4820-00-355-3994, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division. Government technical data includes 21 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 4 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-00-355-3994 |
| Primary Part Number | S8603 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division |
| Status | ACTIVE |
| Flow Control Device | BALL |
| Connection Style | PLAIN (PIPE) FIRST END |
| Connection Style | PLAIN (PIPE) SECOND END |
| Connection Type | THREADED EXTERNAL PIPE SECOND END |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | ANGLE |
| Features Provided | VALVE STEM LOCK SHIELD |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.250 INCHES FIRST END IN |
| Nominal Thread Size | 0.250 INCHES SECOND END IN |
| Maximum Operating Temp | 250.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Material | COPPER ALLOY BODY |
| Material | STEEL FLOW CONTROL DEVICE |
| Material | STEEL STEM |
| Material | COPPER ALLOY SEAT |
| Thread Series Designator | NPT SECOND END |
| Thread Series Designator | NPT FIRST END |
| Opening Pressure Setting | 180.0 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 |
| Part Number | Manufacturer |
|---|---|
| S8603 PRIMARY | Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division (USA) |
| 125 | F.c.kingston Co. Dba Storm Manufacturing (USA) |
| Reference | Meaning |
|---|---|
| S8603 | 5/9 Secondary reference Compair Kellogg Div of Robertshaw Controls Co |
| 38436 | 5/9 Secondary reference Compair Kellogg Div of Robertshaw Controls Co |
| 8603SIZE1-4 180PS1 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-355-3994 is a Valve,safety Relief, manufactured by Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-355-3994 has 2 manufacturer part numbers on file: S8603 (Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division), 125 (F.c.kingston Co. Dba Storm Manufacturing).
4 possible matches (shared part number, not a government interchangeability claim): 6150-00-868-7815, 5360-01-082-9991, 5935-01-278-7164. Verify interchangeability with system specifications before substitution.
Key specifications for S8603: Flow Control Device: BALL; Connection Style: PLAIN (PIPE) FIRST END; Connection Style: PLAIN (PIPE) SECOND END; Connection Type: THREADED EXTERNAL PIPE SECOND END. 21 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.