Bushing, MPT x FPT (Flush Style) PVC Schedule 80 1-1/2" x 3/4" (839-210)

The 839-210 is a 1-1/2" × 3/4" PVC Schedule 80 Flush Bushing with a 1-1/2" male pipe thread (MPT) on its outer surface and a 3/4" female pipe thread (FPT) on its inner bore, designed to insert into any standard 1-1/2" female-threaded fitting and reduce the internal thread engagement point to 3/4" — allowing a 3/4" male NPT fitting, nipple, valve, or instrument body to thread directly into what would otherwise be a 1-1/2" threaded opening. The flush style means the bushing seats flush with or recessed within the face of the receiving 1-1/2" FPT fitting, presenting no external shoulder or hex flats proud of the fitting face — a compact, low-profile geometry suited for tight assemblies and panel-mounted applications where the protruding shoulder of a hex bushing would interfere with adjacent components or fitting faces.

Manufactured from dark gray PVC Schedule 80 compound and compliant with ASTM D2464, this bushing carries NSF/ANSI 61 certification for potable water contact. As an all-threaded fitting — with NPT threads on both the exterior and interior — no solvent cement is involved at either connection point. The 1-1/2" MPT exterior threads into the receiving FPT fitting with PTFE thread tape or appropriate pipe thread sealant; the 3/4" FPT interior receives the mating 3/4" male NPT component with the same thread sealant treatment applied to its male threads. The result is a fully threaded, fully serviceable assembly at both the bushing-to-fitting interface and the component-to-bushing interface — either connection can be broken and reassembled without tools beyond a strap wrench or appropriate PVC-safe wrench on the receiving fitting body.

The heavier Schedule 80 wall thickness is particularly meaningful in a flush bushing at this size reduction. The 1-1/2" × 3/4" reducing step removes substantial material from the bushing body between the outer MPT threads and the inner FPT bore — the wall section between the two thread forms is thinner than in a same-size or one-step reducing bushing, and the Schedule 80 compound provides the additional structural integrity and thread-root depth needed to maintain pressure capacity and resist stress cracking at the threads under sustained operating pressure, vibration, or thermal cycling. A Schedule 40 flush bushing at this size reduction carries meaningfully less thread-root stock and is more susceptible to cracking in demanding service environments.

The 1-1/2" × 3/4" size combination — a two-pipe-size reduction in a single threaded bushing — is a practical specification wherever a 1-1/2" FPT port on a valve body, tank fitting, pump housing, manifold, or pipe union must be reduced to accept a 3/4" male NPT instrument, nipple, or service component. Rather than threading a 1-1/2" nipple into the port and then reducing through a separate adapter, the flush bushing inserts directly into the 1-1/2" FPT opening and presents a 3/4" FPT bore in one compact, low-profile step — reducing part count, thread engagement points, and the overall assembly length at the connection.

Installation requires no solvent cement at either end. Apply PTFE thread tape or an appropriate pipe thread sealant to the 1-1/2" MPT threads of the bushing before threading it into the receiving 1-1/2" FPT fitting — hand-tight plus the appropriate number of wrench turns per standard NPT assembly practice. Apply thread sealant separately to the 3/4" male NPT threads of the mating fitting or nipple before threading it into the 3/4" FPT bore of the installed bushing. The governing pressure rating for the assembled connection is determined by the 3/4" FPT inner bore as the smaller and more restrictive end; consult the manufacturer's published technical data for the confirmed working PSI at this size combination before finalizing system design.

Specifications

Industries & Applications

• Industrial Process Piping — Size reduction at 1-1/2" female-threaded ports on valves, manifolds, pump housings, and tank fittings in process water, cooling water, and chemical transfer systems where a 3/4" male NPT instrument, nipple, or service component must engage a larger-bore threaded port without a multi-fitting adapter chain at the connection point
• Chemical Handling — Compact threaded reductions in corrosion-resistant Schedule 80 PVC chemical distribution and reagent handling assemblies where the flush profile prevents interference with adjacent fitting faces or panel surfaces and the two-pipe-size reduction eliminates an intermediate adapter at the port connection
• Water Treatment & Purification — Port reductions at 1-1/2" FPT filter housings, chemical dosing equipment bodies, and treatment system manifold ports in municipal and industrial water treatment installations where 3/4" male NPT service lines, gauges, or dosing inlets must engage a larger-bore threaded port directly
• Instrumentation & Controls — Instrument port adapters at 1-1/2" FPT valve bodies, flow meter housings, and process equipment ports where pressure gauges, temperature sensors, sampling valves, and other 3/4" male NPT instrument bodies must be installed at a larger-bore threaded opening in a compact, low-profile configuration
• Commercial Plumbing — Threaded port reductions at 1-1/2" FPT valve bodies, union nuts, and equipment connections in commercial mechanical rooms where a 3/4" male NPT service line or component must engage a larger-bore threaded port without introducing additional fitting length into a constrained assembly
• Irrigation & Agriculture — Port reductions at 1-1/2" FPT valve bodies, backflow preventer ports, and pump manifold connections in Schedule 80-rated high-pressure agricultural and turf irrigation systems where 3/4" male NPT service components must interface with larger-bore threaded equipment ports
• Panel & Manifold Assemblies — Flush-profile port reductions in PVC manifold blocks, panel-mounted valve assemblies, and bulkhead fitting installations where the absence of external hex flats allows the bushing to seat fully within the receiving fitting face — enabling adjacent components to be positioned closer together than a hex bushing profile would permit