Parts for Superheated Water Boilers & Steam/Vapor Generation Boilers

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.