1-1/4" Brass Threaded Swing Check Valve (1104NL)

The 1104NL is a 1-1/4-inch lead-free brass threaded swing check valve engineered for automatic, non-return backflow prevention on water supply, steam, and compatible fluid service piping systems where preventing reverse flow at the check valve location is a system performance, equipment protection, or safety requirement — and where lead-free (NL) brass construction meets the potable water material compliance requirements of the federal Reduction of Lead in Drinking Water Act and the state and local plumbing codes that mandate lead-free wetted surface materials across all potable water system components.

The 1-1/4-inch diameter occupies the same deliberate hydraulic sizing position in check valve specifications that it holds in ball valve and fitting specifications — a size that is less universally present than 1-inch or 1-1/2-inch in standard residential and light commercial plumbing but that appears with regularity in commercial, industrial, and process system applications where 1-1/4-inch is the hydraulically correct pipe size for the specific flow condition at the non-return location. In commercial plumbing systems, HVAC hydronic distribution, and light industrial process water supply, a 1-1/4-inch check valve at a specific non-return location reflects a deliberate hydraulic design decision — the pipe at that location is sized at 1-1/4-inch because the flow rate served by that branch falls between the capacity appropriate for 1-inch and the larger capacity of 1-1/2-inch — and the 1104NL is the non-return valve specification that correctly serves that deliberate design sizing decision.

As the middle size between the 1105NL (1-1/2-inch) and the 1-inch size in the lead-free brass swing check valve series, the 1104NL completes the 1-1/4-inch position in the check valve line — providing the non-return protection specification for the specific intermediate flow capacity tier that 1-1/4-inch pipe represents in commercial and industrial system design. For commercial plumbing contractors, mechanical engineers, and HVAC system designers who encounter 1-1/4-inch pipe at non-return locations in their system designs, the 1104NL is the lead-free brass swing check specification that correctly serves that size without pipe reduction, size substitution, or fitting modification that would introduce unnecessary flow restriction or hydraulic inefficiency at the non-return location.

The swing check valve design delivers the same automatic passive non-return protection at 1-1/4 inches that defines the swing check mechanism across the full size series — a hinged clapper disc that swings open under forward flow pressure and closes under gravity and reverse flow pressure without external power, control signals, or operator intervention. The mechanical simplicity of this passive operation principle is the fundamental performance characteristic that makes swing check valves the dominant backflow prevention specification for general-purpose non-return applications across the full range of commercial plumbing, HVAC, steam, and mechanical system service — the valve operates correctly and reliably across its full service life with the same passive mechanical response to flow direction on the ten-thousandth cycle as on the first, requiring no calibration, no power supply maintenance, and no operator action between installation and eventual replacement.

The lead-free (NL) designation confirms compliance with the federal Reduction of Lead in Drinking Water Act's weighted average 0.25% lead limit on wetted surfaces — the same compliance standard that applies across the full lead-free brass check valve series and that is the non-negotiable material compliance requirement for potable water system components across all commercial and municipal plumbing jurisdictions in the United States. The NL designation on the 1104NL is the specification confirmation that commercial plumbing contractors, mechanical engineers, and plumbing inspectors need to confirm code compliance at the 1-1/4-inch non-return valve locations of commercial potable water systems without additional material documentation or variance requests.

The threaded NPT end connections provide direct inline installation with standard pipe thread sealant or PTFE tape, no welding or flange hardware required, compact installation format for the confined equipment connections and secondary distribution branch locations where 1-1/4-inch check valves are most commonly encountered, and future removal by unthreading for inspection or replacement without cutting or modifying the surrounding piping system.

Specifications

Industries & Applications

The 1104NL is the lead-free brass swing check valve specification for 1-1/4-inch non-return backflow prevention across the commercial, institutional, and light industrial applications where 1-1/4-inch is the hydraulically correct pipe size at the non-return location:

• Commercial Domestic Water — Intermediate Branch & Sub-Zone Supply — Intermediate branch supply check valve locations on commercial domestic water systems where 1-1/4-inch sub-zone supply branches from 1-1/2-inch or 2-inch distribution mains require non-return protection at the branch takeoff; the 1104NL lead-free brass NL construction meets potable water material compliance requirements at the intermediate distribution check valve positions that appear in large commercial buildings, institutional facilities, and multi-story residential buildings where hydraulic zone design produces 1-1/4-inch branch sizing between the primary supply main and the terminal fixture supply tier.
• HVAC Hydronic System — Intermediate Zone & Equipment Connections — Non-return protection at 1-1/4-inch zone supply connections, intermediate distribution branch points, and individual equipment supply connections in commercial HVAC hydronic heating and cooling systems where 1-1/4-inch appears at the intermediate zone supply tier between the primary distribution main and the individual terminal equipment supply connections; prevents reverse flow through intermediate zone branches when zone pumps cycle off and maintains zone hydraulic isolation at intermediate distribution points in multi-zone hydronic systems.
• Commercial Booster Pump — Intermediate Capacity Applications — Discharge non-return protection on 1-1/4-inch intermediate capacity booster pumps and zone circulation pumps on commercial domestic water and HVAC hydronic systems where pump sizing produces a 1-1/4-inch discharge connection; the 1104NL prevents back-spinning and reverse flow through the pump body when the pump cycles off or loses prime on intermediate capacity pump applications where the discharge connection falls at 1-1/4-inch.
• Steam Distribution — Intermediate Branch Non-Return — Non-return protection on 1-1/4-inch steam distribution branch connections and individual terminal heating equipment supply lines where the specific terminal equipment flow rate produces a 1-1/4-inch pipe sizing result at the non-return location; prevents steam and condensate backflow at intermediate branch connection points in industrial and commercial steam distribution systems; confirm temperature and pressure ratings against specific steam system operating conditions before specifying.
• Light Commercial & Institutional Plumbing — Non-return valve locations in light commercial office buildings, schools, healthcare facilities, and institutional buildings where hydraulic system design produces 1-1/4-inch branch sizing at specific non-return locations between the primary supply main and terminal supply connections; the 1104NL correctly serves these intermediate non-return locations without the flow restriction of a pipe reduction or the hydraulic inefficiency of oversizing the check valve relative to the actual pipe size at the non-return location.
• Multi-Family Residential Building Supply — Non-return protection at 1-1/4-inch building supply branch connections and domestic hot water recirculation zone supply points in multi-family residential buildings and apartment complexes where 1-1/4-inch appears at intermediate branch supply positions between primary building supply mains and apartment cluster supply branches; lead-free NL compliance meets residential building plumbing permit requirements across all U.S. jurisdictions.
• Light Industrial Process Water & Cooling — Non-return protection at 1-1/4-inch process water supply connections, cooling water branch supply lines, and utility water distribution branches in light industrial and manufacturing facilities where the flow rate at the non-return location produces a 1-1/4-inch pipe sizing result and where the fluid chemistry is within the brass body compatibility range; confirm chemical compatibility with the specific process fluid before specifying in non-standard water service applications.
• Commercial Kitchen & Food Service Equipment — Non-return protection on 1-1/4-inch commercial kitchen equipment supply connections — dishwasher supply lines, steam kettle connections, and combination oven supply branches — where the specific equipment supply flow rate and code compliance requirements produce a 1-1/4-inch check valve specification at the individual equipment supply connection; lead-free NL construction meets the potable water material compliance requirements of commercial kitchen plumbing permits and health department inspections.