WordNet records no synonym and no antonym for reflux condenser. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
condenser such that vapor over a boiling liquid is condensed and flows back into the vessel to prevent its contents from boiling dry
Synonyms, antonyms and the broader and narrower relations for reflux condenser come from Princeton University’s WordNet. Full sources and licences.