Bushing, Spigot x FPT (Flush Style) PVC Schedule 80 4" x 3" (838-422)

The 4" x 3" PVC Schedule 80 Flush Bushing (838-422) transitions a 4" solvent-welded socket connection down to a 3" female-threaded outlet in a single compact fitting — with a flush-style profile that seats recessed within the mating 4" socket rather than projecting outward from its face. The spigot end solvent-welds permanently into any standard 4" Schedule 80 slip socket upstream, while the 3" FPT outlet accepts any standard 3" male-threaded fitting, valve, nipple, or equipment connection downstream.

The mixed spigot-and-thread configuration is the defining characteristic of the 838-series and the primary reason it is specified over both the all-slip 837-series and the all-threaded 839-series flush bushings at the same sizes. The solvent-welded spigot inlet creates a permanent, pressure-rated upstream joint that becomes part of the surrounding PVC assembly — matching the structural and chemical performance of the Schedule 80 pipe and fittings on either side — while the 3" FPT outlet preserves downstream serviceability, allowing male-threaded valves, strainers, instruments, or equipment connections at the 3" port to be removed and replaced without disturbing the permanent upstream joint. This combination of a fixed upstream connection and a removable downstream connection is a deliberate design choice in systems where the bushing itself is a permanent transition point but the equipment or fitting at the downstream threaded port will require periodic service, replacement, or reconfiguration over the system's life.

The 4" to 3" size step-down is a single nominal pipe size increment — a moderate, controlled reduction that suits systems where the downstream 3" threaded connection must still carry substantial flow. Common applications include valve isolation points where a 4" solvent-welded header steps down to a 3" threaded valve body, pump suction or discharge connections where the system transitions from a solvent-welded 4" Schedule 80 run to a 3" threaded equipment port, and equipment manifold assemblies where a permanent 4" slip-welded inlet feeds a serviceable 3" threaded outlet at an equipment interface.

The flush-style profile keeps the fitting recessed within the 4" socket — avoiding the clearance problems and installation constraints that a protruding hex bushing would introduce in tight mechanical spaces, close-coupled valve assemblies, and congested equipment rooms where a hex head would interfere with adjacent components or reduce working clearance to unacceptable levels.

Manufactured to Schedule 80 specifications and dimensionally compliant with ASTM D2467, the 838-422 delivers the elevated wall thickness and pressure rating that Schedule 80 gray PVC is specified for in chemical processing, industrial fluid handling, and demanding commercial applications. Gray PVC construction provides broad chemical compatibility with acids, alkalis, and industrial process fluids. NSF 61 certification confirms suitability for potable water contact where required.

Specifications:

Industries & Applications:

• Chemical Processing — permanent-inlet, serviceable-outlet reducing transitions at valve bodies, pump connections, and equipment ports in 4" chemical feed, dosing, and process fluid systems where the upstream joint is fixed but the downstream 3" threaded connection must remain removable
• Industrial Process Piping — single-step reducing transitions from 4" solvent-welded Schedule 80 headers to 3" threaded valve, instrument, or equipment connections in plant utility and process fluid systems
• Water & Wastewater Treatment — reducing transitions in treatment plant process piping where a permanent 4" slip-welded inlet feeds a serviceable 3" threaded equipment or valve connection
• Commercial & Industrial Plumbing — tight-clearance reducing bushings at valve isolation points and equipment connections in high-pressure mechanical systems where Schedule 40 pressure ratings are insufficient and a flush profile is required
• Aquaculture & Food Processing — corrosion-resistant reducing transitions at equipment and valve connections in recirculating systems and chemical-exposure fluid handling installations where the upstream joint is permanent and the downstream connection requires periodic service
• Irrigation & Agriculture — 4" solvent-welded mainline-to-3" threaded valve or equipment transitions in high-pressure chemical injection and large-scale irrigation distribution systems