Circulation heater / ZHGD Liquid and gas have separate chamber dimensions, tube counts and connections. A model inquiry records the chosen medium; it does not imply the two duties are interchangeable. Flange heater / ZHFL Liquid and gas flange dimensions are listed separately, and U counts can differ. Confirm the medium, materials and vessel interface instead of treating both size sets as one universal parameter. Hazardous-area requirements The source title mentions configurable explosion-proof heaters. Check certificates, ratings and validity against the area, medium, temperature and applicable standards.
Selection guide
Liquid and gas: start on the right table.
Both ZHGD and ZHFL keep liquid and gas as separate fields. Check dimensions, tube counts and connections with the medium.