The Core Assembly,fluid Heater,indus, cataloged under National Stock Number 4420-01-235-2746, is classified within Federal Supply Class 4420 (Heat Exchangers and Steam Condensers) of the Furnace, Steam, Drying, Nuclear Reactors group. The manufacturer of record is Johnston Boiler Company. Government technical data includes 5 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4420-01-235-2746 |
| Primary Part Number | 20877 |
| Item Name | Core Assembly,fluid Heater,indus |
| FSC / FSG | 4420 / 44 — Heat Exchangers and Steam Condensers |
| Manufacturer | Johnston Boiler Company |
| Status | ACTIVE |
| Heat Transfer Method | INDIRECT |
| Style Designator | STRAIGHT PLAIN TUBE, CYLINDRICAL |
| Core Diameter | 28.500 INCHES NOMINAL IN |
| Core Length | 38.250 INCHES NOMINAL IN |
| Material | STEEL OVERALL |
| 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 |
|---|---|
| 20877 | Johnston Boiler Company (USA) |
| Reference | Meaning |
|---|---|
| 11P3-009 | 3/2 Design control — primary reference U.S. Government activity |
NSN 4420-01-235-2746 is a Core Assembly,fluid Heater,indus, manufactured by Johnston Boiler Company, classified under FSC 4420, Heat Exchangers and Steam Condensers. Status: active.
NSN 4420-01-235-2746 has 1 manufacturer part number on file: 20877 (Johnston Boiler Company).
2 possible matches (shared part number, not a government interchangeability claim): 6645-01-318-6056, 5998-01-371-2527. Verify interchangeability with system specifications before substitution.
Key specifications for 20877: Heat Transfer Method: INDIRECT; Style Designator: STRAIGHT PLAIN TUBE, CYLINDRICAL; Core Diameter: 28.500 INCHES NOMINAL IN; Core Length: 38.250 INCHES NOMINAL IN. 5 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.