Download PDFs of Aprilaire owners manuals for existing and discontinued Aprilaire products here. Organized by product type. Link to PDF reader included. Aprilaire Zoned Comfort Control 6403 Pdf User Manuals. View online or download Aprilaire Zoned Comfort Control 6403 Safety & Installation Instructions. Below are manuals, spec sheets, and install guides for AprilAire Zoning products. Archived and discontinued product information is also listed. Skip to Specifications Section The Aprilaire 6403 3-Zone Panel is designed to work with heat pump or 6403 Aprilaire 6403 Installation Manual.Read this installation manual before beginning installation of the Aprilaire®. Zoned Comfort Control® system. For questions call Aprilaire customer.