F1790 Indirect Waste Funnel with Backwater Valve Home » Products » Specification Drainage Products » Funnel/Indirect Waste Drains » F1790 Indirect Waste Funnel with Backwater Valve MIFAB® F1790 Series lacquered cast iron indirect waste funnel with backwater valve. Specification Sheet Catalog Catalog List Pricing Current Catalog: MPB-2022 Downloads Downloads Features & Benefits Typical Installations Outlet Selection Guide All Star Cover Flyer Drain Specifications Floor Drain Selection Guide Videos Videos Top Set Drain Demonstration All-Star Drain Video Return to Products