<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31321800</termId><termName>heating systems</termName><termType>PT</termType><termNote><![CDATA[ Assemblies of interrelated equipment designed to provide heat to buildings and other structures. ]]></termNote><termCreatedDate>2026-03-30 20:26:45</termCreatedDate><relation><relationType>UF</relationType><termId>31321801</termId><termName>building heating systems</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31321802</termId><termName>heating</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31321803</termId><termName>heating system</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31321804</termId><termName>systems, heating</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31306790</termId><termName>HVAC</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31346584</termId><termName>furnaces</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31346548</termId><termName>resistance heating</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31346555</termId><termName>hot water heating</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31346560</termId><termName>radiant heating</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31346564</termId><termName>solar heating</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31346567</termId><termName>steam heating</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31346572</termId><termName>warm air heating</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31322116</termId><termName>heat-distributing units</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31353034</termId><termName>heating equipment</termName><termType>PT</termType></relation></term>  </Zthes>