U.S. imports of Parts for Superheated Water Boilers & Steam/Vapor Generation Boilers (HS 840290) totaled $45.7M in August 2026, imported from 35 countries.
Importers of Parts for Superheated Water Boilers & Steam/Vapor Generation Boilers paid $7.2M in duties in August 2026, an average duty rate of 15.69% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule. Parts for Superheated Water Boilers & Steam/Vapor Generation Boilers imports of $45.7M in August 2026 ran 34% above the year-to-date monthly average of $34.2M.
Last updated: August 2026 dataReplacement and OEM components for industrial steam generators and superheated water boilers — excluding parts for central heating boilers — split into two US tariff lines: heat exchangers (8402900010) and all other parts (8402900090). Heat exchangers are singled out because they are widely traded as standalone industrial components and may otherwise be claimed under competing headings. Importers of boiler parts should confirm that the component is specifically designed for steam or vapor generation service, as general-purpose fittings or valves may classify under their own functional headings rather than here.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
356 import shipments a month
Heat exchangers (8402900010) are separated because they are high-value, widely traded components that also appear in many non-boiler applications. Isolating them within the boiler parts heading allows for more precise trade data collection and may affect applicable duty rates or trade-remedy exposure compared to the catch-all parts line (8402900090).
No. Heading 840290 explicitly excludes parts for central heating hot water boilers, which are covered under heading 840390. If a component is interchangeable between both boiler types, classification follows the principal use or, if that cannot be determined, the heading that appears last in numerical order under GRI 3(c). A binding ruling from CBP is advisable for dual-use parts.
Subheading 1 of 5 in heading 8402
Subheading 840290 · $45.7M of $53.1M
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Imports for consumption | Average duty rate | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 8402900090 | Pts for Steam, Vapor Generating, Super-Heat Wtr Blrs | $39.4M | 17.02% | 95.98% | $6.7M |
| 8402900010 | Heat Exchangers | $6.4M | 7.45% | 98.03% | $475K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 8402900090 | Parts Steam, Vap Gen, Sup-Heat Wtr Blrs, Ex Ht Exch | $5.8M |
| 8402900010 | Heat Exchangers | $1.1M |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
ImportsExports
Imports
$45.7MYoY · free account
Exports
$7.0MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $308.5M of Parts for Superheated Water Boilers & Steam/Vapor Generation Boilers and exported $81.5M.
Through August 2026. Source: U.S. Census Bureau.
Imports · August 2026
origin
Vietnam and South Korea together supply 70% of it. China pays 39.7% duty; Italy 0.4%.
customs district
entry
rate provision · imports
3.7% enters free of duty; duty collected equals 15.69% of imports for consumption.
Trade Directory
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