PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

1543DValve,safety Relief

Ashcroft Inc Dba Heise · NSN 4820-00-900-3800 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-00-900-3800 — this item is cataloged by the U.S. Government under National Stock Number 4820-00-900-3800. Primary manufacturer part number: 1543D.
Features
  • Valve,safety Relief — FSC 4820
  • Thread Series Designator: NPT ALL ENDS
  • Style Designator: ANGLE
  • Opening Pressure Setting: 125.0 POUNDS PER SQUARE INCH LBS
  • Material: IRON CAST BODY
  • Flow Control Device: DISK
  • Valve Operation Method: AUTOMATIC
  • Thread Direction: RIGHT-HAND ALL ENDS
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Iron Cast Body construction
General Description

The Valve,safety Relief, cataloged under National Stock Number 4820-00-900-3800, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Ashcroft Inc Dba Heise. Government technical data includes 18 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 5 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 4 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN4820-00-900-3800
Primary Part Number1543D
Item NameValve,safety Relief
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerAshcroft Inc Dba Heise
StatusCANCELLED
Thread Series DesignatorNPT ALL ENDS
Style DesignatorANGLE
Opening Pressure Setting125.0 POUNDS PER SQUARE INCH LBS
MaterialIRON CAST BODY
Flow Control DeviceDISK
Valve Operation MethodAUTOMATIC
Thread DirectionRIGHT-HAND ALL ENDS
Connection TypeTHREADED EXTERNAL PIPE FIRST END
Bonnet Attachment MethodINTEGRAL
Disk Loading MethodSPRING
Nominal Thread Size0.500 INCHES SECOND END IN
Connection StylePLAIN (PIPE) FIRST END
Connection StylePLAIN,OPTIONAL END(PIPE) SECOND END
Connection TypeTHREADED INTERNAL PIPE SECOND END
Nominal Thread Size0.750 INCHES FIRST END IN
Furnished Items and Quantity1 LEVER
Bonnet TypeINSIDE SPRING
Operating Pressure250.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 4
4820-00-269-7591 INTERCHANGEABLE
Valve,expansion
5330-00-700-853618217 INTERCHANGEABLE
Gasket E,haust Mani
Dana Automotive Systems Group, Llc Dba Dana Sealing Products
2995-00-909-993918217 INTERCHANGEABLE
Cover,indicator,val
Eaton Aerospace Llc Dba Eaton Aerospace Jackson
5995-01-727-882218217 INTERCHANGEABLE
Cable Assembly,special Purpose,e
The First Electronics Corporation
Cross-Reference Index
Part NumberManufacturer
1543-1-2INRNG12010130PSI Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse (USA)
1543-1-2INRNG120TO130PSI Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse (USA)
1543D Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse (USA)
18217 Clayton Manufacturing Company (USA)
1543D PRIMARY Ashcroft Inc Dba Heise (USA)
Related Parts
4820-00-269-7591INTERCHANGEABLE
VALVE,EXPANSION
5330-00-700-8536INTERCHANGEABLE
GASKET E,HAUST MANI
18217
2995-00-909-9939INTERCHANGEABLE
COVER,INDICATOR,VAL
18217
5995-01-727-8822INTERCHANGEABLE
CABLE ASSEMBLY,SPECIAL PURPOSE,E
18217

Frequently Asked Questions

What is NSN 4820-00-900-3800?

NSN 4820-00-900-3800 is a Valve,safety Relief, manufactured by Ashcroft Inc Dba Heise, classified under FSC 4820 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 4820-00-900-3800?

NSN 4820-00-900-3800 has 5 cross-referenced part numbers: 1543-1-2INRNG12010130PSI (Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse), 1543-1-2INRNG120TO130PSI (Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse), 1543D (Dresser, Inc. Dba Dresser Equipment Group Div Industrial Valve Operations, Dresse), 18217 (Clayton Manufacturing Company), 1543D (Ashcroft Inc Dba Heise).

What NSN replaces 4820-00-900-3800?

There are 4 known substitutes for 4820-00-900-3800: 4820-00-269-7591, 5330-00-700-8536, 2995-00-909-9939 and 1 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 1543D?

Key specifications for 1543D: Thread Series Designator: NPT ALL ENDS; Style Designator: ANGLE; Opening Pressure Setting: 125.0 POUNDS PER SQUARE INCH LBS; Material: IRON CAST BODY. 19 total characteristics are documented in the Federal Logistics Information System.

Is NSN 4820-00-900-3800 still in active supply?

NSN 4820-00-900-3800 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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