Bushing, Spigot x Slip (Flush Style) PVC Schedule 80 4" x 3" (837-422)

The 837-422 is a 4" x 3" Schedule 80 PVC Flush Style Bushing with a Spigot x Slip configuration. This fitting reduces pipe size inline — the spigot (male) end is sized to the OD of 4" PVC pipe, allowing it to insert directly into any standard 4" slip socket fitting or valve, while the slip (female) socket on the opposite end accepts 3" PVC pipe for solvent cementing. Both ends are solvent-weld connections, making the entire assembly a fully cemented, permanent, pressure-rated reduction with no threads involved.

The "flush style" designation distinguishes this bushing from a hex bushing. Where a hex bushing has a raised hexagonal shoulder that sits proud of the socket face, the flush style bushing sits completely flush within the receiving fitting — the shoulder does not protrude beyond the face of the socket it is inserted into. This produces a cleaner, more compact assembly profile that is preferred in tight installations, close-coupled equipment connections, and applications where a protruding hex shoulder would interfere with adjacent fittings, flanges, or structural elements.

The spigot x slip configuration is specifically designed to nest inside an existing fitting rather than connecting pipe end to pipe end — the spigot inserts into a 4" tee, cross, coupling, or valve socket, effectively converting that 4" port to a 3" slip socket in place. This makes the flush bushing a highly efficient reducing solution when a 4"-ported fitting is already installed or specified and a 3" branch or continuation is required, without needing to replace the larger fitting or introduce an additional coupling into the line.

At this size step — 4" to 3" — the 837-422 is a fitting commonly found on pump discharge assemblies, header-to-branch transitions, equipment connection points, and distribution manifolds in commercial and industrial systems where flow is intentionally reduced between the main and a branch or sub-circuit. Schedule 80 wall thickness ensures the fitting meets the pressure demands of industrial chemical, water treatment, and process piping environments where a Schedule 40 bushing would be underspecified.

Specifications:

⚠️ Note: In a reducing fitting, the smaller end governs the pressure rating. The spigot end must be fully seated into the receiving socket before cementing — ensure the spigot is inserted to full depth and held firmly during the set period. Consult manufacturer derating tables for elevated-temperature applications.

Industries & Applications:

• Chemical Processing — Converts 4"-ported valves, tees, and manifold bodies to 3" branch connections inline without replacing the larger fitting, keeping chemical line assemblies compact and reducing joint count in corrosive-service piping
• Water & Wastewater Treatment — Used at header-to-branch transition points on treatment plant distribution piping where flow is stepped down from a 4" main to a 3" sub-circuit or equipment feed line
• Industrial Process Piping — Reduces fitting count on process skids and modular assemblies where a 4" fitting socket must be adapted to accept 3" pipe without introducing an additional coupling or spool piece
• Pump Station & Equipment Connections — Inserted into 4" valve or fitting sockets at pump discharge or suction connections where the connected pipe or equipment port is 3", allowing the reduction to occur within the existing fitting footprint
• Irrigation & Agricultural Systems — Transitions large-diameter 4" supply headers down to 3" distribution laterals at manifold branch points where a compact, flush-profile reduction is preferred over a hex bushing in tight valve boxes or enclosures
• Municipal & Utility Infrastructure — Applied on large-diameter PVC assemblies in valve vaults and metering stations where a flush profile reduction is required to maintain clearances within confined installation spaces