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The MUELLER STREAMLINE ABSCOUP3112 is an ABS DWV reducing coupling designed to connect drain, waste, and vent piping where a 3-inch line transitions to a 1.5-inch line. The hub-by-hub (H x H) end configuration accepts standard ABS pipe on both ends, allowing solvent-cement joints for a permanent, leak-resistant connection. This fitting is used in gravity-flow drainage systems found in residential and light commercial construction. Licensed plumbers and pipefitters install this coupling as part of DWV rough-in work behind walls, in floor assemblies, and in exposed drain runs.
This reducing coupling is suited for drain, waste, and vent applications where pipe size must step down along a drainage run. Typical uses include reducing a main stack branch to a smaller fixture drain, connecting lavatory or utility sink drains into a larger trunk line, and similar transitions in sanitary drainage systems. The fitting is intended for non-pressure, gravity-flow service as required by standard DWV system design.
Designed as an OEM-style replacement and new-installation fitting for ABS DWV piping systems using standard 3-inch and 1.5-inch schedule pipe dimensions.
Installation must be performed by a licensed plumber in accordance with the applicable plumbing code, such as the IPC or UPC. Clean and deburr pipe ends before applying ABS solvent cement; use a cleaner and cement rated for ABS pipe. Ensure the fitting is fully seated and aligned before the cement sets, as ABS solvent joints are permanent. DWV systems must be pressure-tested and inspected per local jurisdiction requirements before covering rough-in work.
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