Reducer Bushing, Spigot x Slip PVC Schedule 40 5" x 4" (437-490)

The 437-490 is a PVC Schedule 40 reducer bushing that steps a 5" socket connection down to accept 4" pipe using a spigot × slip end configuration. The 5" spigot (male plain end) inserts directly into any existing 5" socket fitting — a tee, coupling, valve body, or other Schedule 40 socket — while the 4" slip socket on the opposite end receives 4" IPS pipe for a standard solvent-cement joint.

This end geometry is what distinguishes a reducer bushing from a reducing coupling. A reducer bushing's large end is male, designed to nest inside an existing fitting socket rather than acting as a standalone inline connector. This makes it particularly useful when a size reduction is needed at a fitting outlet or branch — a tee branch, a cross port, or a fitting end connection — without introducing an additional spool piece or coupling into the assembly.

At 5" × 4", this is a large-diameter fitting that warrants careful solvent cement technique. Both mating surfaces should be cleaned, primed with a compatible PVC primer, and coated with a heavy-bodied PVC solvent cement rated for large-diameter schedule pipe. Full circumferential coverage is essential at these diameters — partial contact can leave dry spots that compromise joint integrity under pressure. Fittings of this size should be aligned immediately after joining and held firmly in position for a minimum of 30 to 60 seconds while the initial bond sets. Allow full cure time before pressurizing, following cement manufacturer specifications for the ambient temperature and pipe diameter.

Manufactured from rigid PVC Type I, Grade I (Cell Classification 12454) to ASTM D2466, the 437-490 offers broad chemical resistance to acids, bases, salts, and many industrial fluids. NSF/ANSI 61 certification confirms suitability for potable water contact. The 5" spigot end governs the pressure rating for the assembly, as the larger end carries a lower pressure rating than the 4" outlet in Schedule 40 at this size range.

Specifications:

Industries & Applications:

• Municipal Water & Wastewater Systems — Large-diameter step-downs at fitting outlets, tee branches, and distribution manifolds in water main and collection system infrastructure where 5" to 4" reductions are common transition points
• Industrial & Chemical Processing — Reducing large-bore process headers to 4" branch lines or equipment inlets in corrosive service environments where metal fittings are unsuitable
• Irrigation & Agricultural Infrastructure — Bushing-in reductions at tee outlets and mainline fittings in large-scale center pivot, drip, and gravity-fed irrigation systems with 5" primary mains
• Commercial Plumbing & Mechanical — Diameter reductions at existing 5" socket fittings during renovation, expansion, or system modification work without full fitting replacement
• Drainage & Stormwater Systems — Step-down connections in gravity drainage networks, retention basin outlet structures, and stormwater conveyance piping where 5" to 4" transitions occur at junction fittings
• Swimming Pool & Aquatic Facility Piping — Reducing connections in large recirculation and backwash systems where main headers transition to 4" equipment feed or return lines