Reducing Tee, Slip x Slip x Slip PVC Schedule 40 1-1/4" x 1-1/4" x 1/2" (401-166)

This 1-1/4" × 1/2" Schedule 40 PVC Reducing Tee provides a reducing solvent-cemented branch outlet off a 1-1/4" PVC main run, with equal 1-1/4" slip socket run ports maintaining the straight-through flow path of the main and a reducing 1/2" slip socket branch outlet providing a small-bore perpendicular branch connection. All three ends accept their respective PVC pipe sizes for solvent cement joining. The run continues at the full 1-1/4" diameter through both run ports — the three-step size reduction occurs only at the branch, not at the run.

Within the 401-series 1-1/4" run sub-group, the 401-166 makes the deepest branch reduction — a three-step transition from the 1-1/4" run size down to a 1/2" branch outlet. This deepest-reduction positioning distinguishes it from the 401-167 (1-1/4" × 1-1/4" × 3/4"), which makes a shallower two-step reduction to a 3/4" branch serving zone supply runs, secondary distribution lines, and standard equipment connections. The 401-166 branches at 1/2" — three steps below the 1-1/4" run — serving the more specifically defined small-bore niche of chemical dosing connections, instrument supply branches, solenoid valve supply lines, small equipment feeds, and fine-bore secondary connections that draw from 1-1/4" transitional runs at flow rates well below 3/4" capacity. The branch outlet size is the sole selection criterion between the two 1-1/4" run reducing tees: a 3/4" downstream branch requires the 401-167; a 1/2" downstream branch requires the 401-166.

The 401-166 also has a direct parallel at the 1" run size: the 401-122 (1" × 1" × 1/2", previously written) branches at the same 1/2" outlet but from a 1" run rather than a 1-1/4" run. Both deliver the same 1/2" branch downstream; the run pipe size is the sole selection criterion between them. When the main run is 1" PVC, the 401-122 applies; when the main run is 1-1/4" PVC, the 401-166 is the correct fitting. In systems where the distribution hierarchy progresses from a 1-1/4" transitional secondary header and must tap both 3/4" zone supply branches and 1/2" instrument or dosing connections, the 401-167 and 401-166 serve their respective branch size requirements at different positions along the same 1-1/4" run.

The three-step reduction depth of the 401-166 — from 1-1/4" to 1/2" — is the indicator of its application specificity. Deep branch reductions of this magnitude consistently serve small-bore secondary supply niches in Schedule 40 systems: chemical dosing supply lines connecting dosing pump outlets to the 1-1/4" distribution header, instrument supply branches tapping monitoring lines off the 1-1/4" run, solenoid valve supply connections providing small-bore control signal supply from the transitional-size header, and small equipment feeds drawing modest flow from the 1-1/4" primary run. In each case, the 3/4" or 1" branch capacity would exceed the actual requirement, and the 1/2" branch provides the correct small-bore supply at the tee body without requiring a separate reducer bushing or reducer coupling downstream of the branch connection.

The governing-end pressure rating follows the standard reducing tee convention: the larger 1-1/4" run ports govern the assembly at approximately 280 psi at 73°F. The 1/2" branch socket would independently support a higher pressure at that bore size, but the assembly is governed by the larger run ends — consistent with all reducing tees in this catalog.

Manufactured in white Schedule 40 PVC, this tee delivers reliable performance across residential, commercial, and light industrial piping applications. PVC's resistance to acids, bases, salts, chlorine, and common process fluids provides long service life where metal tees would corrode or scale. NSF/ANSI 61 and NSF/ANSI 14 listings confirm suitability for potable water contact.

Rated to 280 psi at 73°F (governed by the 1-1/4" run port sockets), this fitting handles standard pressure service across irrigation, pool and spa, commercial plumbing, water treatment, and light industrial applications. Three separate solvent-cemented joints must be made at installation. Clean and dry each pipe end and socket interior before application. Apply purple PVC primer to all mating surfaces — both 1-1/4" run port sockets, the 1/2" branch socket, and all three corresponding pipe ends. Apply a uniform coat of Schedule 40 PVC solvent cement to both the pipe end and socket interior at each joint before inserting. Insert each pipe with a slight quarter-turn twist and hold firmly for 30 seconds. Confirm the correct pipe size is aligned to each socket before cementing — the 1-1/4" run port sockets and the 1/2" branch socket are visually distinct given the three-step size differential; confirm which socket faces the branch direction before applying primer. Stagger the three joints where possible and allow full cure time per the cement manufacturer's guidelines before pressurizing. Apply published pressure derating factors for service temperatures above 73°F.

Specifications:

Industries & Applications:

• Commercial & Residential Irrigation — Chemical Dosing & Instrument Branches — Taps a reducing 1/2" solvent-cemented branch off a 1-1/4" Schedule 40 PVC secondary lateral or transitional-size submain at chemical injection connection points, fertilizer injector supply branches, pressure gauge line takeoffs, solenoid valve supply connections, and flow monitoring instrument branches in residential and commercial irrigation systems where the 1/2" branch serves the small-bore chemical treatment and monitoring supply function while the 1-1/4" transitional run continues through the tee at full capacity
• Pump Station & Secondary Distribution Monitoring — Provides a 1/2" reducing branch off a 1-1/4" solvent-cemented Schedule 40 PVC pump discharge secondary header, transitional distribution main, or equipment supply run at chemical dosing connection points, pressure gauge branches, flow switch takeoffs, and instrument supply positions in residential and commercial pump station assemblies where the 1/2" branch serves auxiliary chemical treatment and monitoring functions off the 1-1/4" transitional primary run
• Pool, Spa & Aquaculture Chemical Treatment — Branches a 1/2" chemical dosing supply line off a 1-1/4" solvent-welded Schedule 40 PVC equipment supply or secondary recirculation run at chemical feed connection points, peristaltic pump supply branches, metering valve supply takeoffs, and chemical monitoring instrument connections in residential and commercial pool, spa, and aquatic facility systems where the 1/2" branch serves chemical treatment functions off the 1-1/4" transitional distribution run
• Commercial Plumbing — Small Equipment & Instrument Branches — Provides a 1/2" reducing branch off a 1-1/4" solvent-welded Schedule 40 PVC secondary water supply header at fixture supply connections, small equipment feed branches, pressure gauge line takeoffs, and instrument monitoring supply positions in commercial building water distribution and mechanical room systems where the 1/2" branch serves small-bore secondary supply and monitoring functions off the 1-1/4" transitional header
• Water & Wastewater Treatment — Taps a 1/2" reducing branch off a 1-1/4" Schedule 40 PVC secondary distribution header at chemical dosing supply connections, sampling line branches, instrument supply positions, and small-bore secondary process branches in light-duty municipal and industrial water treatment facilities where the 1/2" branch serves chemical feed and monitoring functions off the 1-1/4" transitional distribution run
• Light Industrial Process Piping — Provides a 1/2" reducing branch off a 1-1/4" solvent-welded Schedule 40 PVC process distribution header at chemical dosing branches, instrument supply connections, solenoid valve supply lines, and small equipment feed positions in light industrial Schedule 40 systems where the 1/2" downstream pipe serves small-bore secondary supply or chemical treatment functions off the 1-1/4" transitional primary process header
• Chemical Dosing & Distribution — Taps a 1/2" solvent-cemented chemical dosing supply branch off a 1-1/4" Schedule 40 PVC chemical feed or distribution header at parallel dosing circuit branch positions, reagent distribution takeoffs, and secondary chemical supply connections in light-duty Schedule 40 chemical dosing systems where the 1/2" branch serves the dosing or chemical distribution supply requirement off the 1-1/4" transitional primary header