PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

BT400-40-1AHeater,duct Type,portable

Engineered Air Systems, Inc. Dba Drs Sustainment Systems · NSN 4520-00-223-3221 · FSC 4520 · No Item Name Available
Verified by PartsTable
NSN 4520-00-223-3221 — this item is cataloged by the U.S. Government under National Stock Number 4520-00-223-3221. Primary manufacturer part number: BT400-40-1A.
Features
  • Heater,duct Type,portable — FSC 4520
  • Surface Treatment: PAINT
  • Air Filter Type: REPLACEABLE PREFORMED
  • Radio Interference Suppression Type: ARMY, MIL-E-53301, RADIO SUPPRESSION
  • Width: 20.000 INCHES NOMINAL IN
  • Heat Outlet Quantity: 1
  • Heat Directing Device: FLEXIBLE DUCTS
  • Fuel Feed Method: INTERNAL PUMP
Applications
  • Industrial maintenance and repair
  • Government and military logistics
  • Equipment overhaul and refurbishment
General Description

The Heater,duct Type,portable, cataloged under National Stock Number 4520-00-223-3221, is classified within Federal Supply Class 4520 (No Item Name Available) of the Plumbing, Heating, and Waste Disposal group. The primary manufacturer of record is Engineered Air Systems, Inc. Dba Drs Sustainment Systems. Government technical data includes 30 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 3 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 5 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4520-00-223-3221
Primary Part NumberBT400-40-1A
Item NameHeater,duct Type,portable
FSC / FSG4520 / 45 — No Item Name Available
ManufacturerEngineered Air Systems, Inc. Dba Drs Sustainment Systems
StatusACTIVE
Surface TreatmentPAINT
Air Filter TypeREPLACEABLE PREFORMED
Radio Interference Suppression TypeARMY, MIL-E-53301, RADIO SUPPRESSION
Width20.000 INCHES NOMINAL IN
Heat Outlet Quantity1
Heat Directing DeviceFLEXIBLE DUCTS
Fuel Feed MethodINTERNAL PUMP
Heat Discharge Outlet TypeSTATIONARY
Fuel Consumption Rate Per Hour4.0 GALLONS
Heat Delivery Rate400000.0 BRITISH THERMAL UNIT
Mounting TypeTRAILER
Maximum Air Flow Rate1070.0 CUBIC FEET PER MINUTE
Ignition MethodELECTRODE
Prime Mover TypeGASOLINE ENGINE
Current TypeAC
Circulated Air TypeHEATED
Speed AdjustmentsSINGLE SPEED
Integral Fuel Tank Capacity16.0 GALLONS
Heat Medium TypeAIR
Current Rating in Amps6.0
Fuel TypeGASOLINE
Heating Element TypeCOMBUSTION CHAMBER
Heat Delivery DirectionHORIZONTAL
PhaseTHREE
Quantity1
Operating Control TypeHAND SWITCH
Height26.000 INCHES NOMINAL IN
Air Circulation DevicePROPELLER FAN
Inclosure MaterialSTEEL
Frequency in Hertz60.0
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 5
4520-00-054-4716 INTERCHANGEABLE
Heater,duct Type,portable
4520-00-203-0224 INTERCHANGEABLE
Heater,duct Type,portable
4520-00-915-7789 INTERCHANGEABLE
Heater,duct Type,portable
4520-00-980-3199PH400 INTERCHANGEABLE
Heater,duct Type,portable
Hdt Expeditionary Systems Inc
4520-01-267-0241 INTERCHANGEABLE
Heater,duct Type,portable
Cross-Reference Index
Part NumberManufacturer
BT400-40-1A Engineered Air Systems, Inc. Dba Drs Sustainment Systems (USA)
BT400-40-1A Drs Environmental Systems Inc (USA)
MILH4607 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
Related Parts
4520-00-054-4716INTERCHANGEABLE
HEATER,DUCT TYPE,PORTABLE
4520-00-203-0224INTERCHANGEABLE
HEATER,DUCT TYPE,PORTABLE
4520-00-915-7789INTERCHANGEABLE
HEATER,DUCT TYPE,PORTABLE
4520-00-980-3199INTERCHANGEABLE
HEATER,DUCT TYPE,PORTABLE
PH400
4520-01-267-0241INTERCHANGEABLE
HEATER,DUCT TYPE,PORTABLE

Frequently Asked Questions

What is NSN 4520-00-223-3221?

NSN 4520-00-223-3221 is a Heater,duct Type,portable, manufactured by Engineered Air Systems, Inc. Dba Drs Sustainment Systems, classified under FSC 4520 (No Item Name Available). Status: active.

What are the part numbers for NSN 4520-00-223-3221?

NSN 4520-00-223-3221 has 3 cross-referenced part numbers: BT400-40-1A (Engineered Air Systems, Inc. Dba Drs Sustainment Systems), BT400-40-1A (Drs Environmental Systems Inc), MILH4607 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M).

What NSN replaces 4520-00-223-3221?

There are 5 known substitutes for 4520-00-223-3221: 4520-00-054-4716, 4520-00-203-0224, 4520-00-915-7789 and 2 more. Verify interchangeability with system specifications before substitution.

What are the specifications of BT400-40-1A?

Key specifications for BT400-40-1A: Surface Treatment: PAINT; Air Filter Type: REPLACEABLE PREFORMED; Radio Interference Suppression Type: ARMY, MIL-E-53301, RADIO SUPPRESSION; Width: 20.000 INCHES NOMINAL IN. 30 total characteristics are documented in the Federal Logistics Information System.

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