Return System 1 : An assembly of connected ducts, air passages, or plenums and fittings through which air from the space or spaces to be conditioned is conducted back to the heat exchanger
NFPA 90B Standard for the Installation of Warm Air Heating and Air-Conditioning Systems, 2009 ed. (Std: Instll of Warm Air Heating and AC Sys - Amer) {236 NFC}
