1-1/2" Brass Threaded Swing Check Valve (1105NL)

The 1105NL is a 1-1/2-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 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 in potable water supply system components.

As the 1-1/2-inch counterpart to the 1106NL (2-inch) in the lead-free brass swing check valve series, the 1105NL serves the next size down in the check valve line — the secondary distribution branches, equipment supply connections, and zone supply mains that feed from the 2-inch primary supply lines where the 1106NL provides non-return protection. In commercial domestic water systems, HVAC hydronic systems, and steam distribution networks, the 1-1/2-inch check valve tier represents the highest-frequency individual non-return valve specification — appearing at the zone supply connections, equipment discharge lines, branch supply check points, and secondary distribution non-return locations that are more numerous in a typical system than the fewer, larger primary supply check valve positions that the 1106NL serves.

The swing check valve design delivers automatic passive non-return protection through the hinged disc mechanism that defines the swing check operating principle — a clapper disc that swings open under forward flow pressure and returns closed under gravity and reverse flow pressure when forward flow stops or reverses. At 1-1/2 inches, the swing check mechanism provides the same fundamental operating simplicity, low head loss flow path, and passive mechanical reliability that makes the swing check the dominant backflow prevention specification for general-purpose non-return applications across commercial plumbing, HVAC, steam, and mechanical system service. No external power, no control signal, and no operator action is required — the valve opens and closes as a direct mechanical response to flow direction, cycle after cycle, across the full service life of the installation.

The 1-1/2-inch diameter is one of the most frequently specified check valve sizes across commercial plumbing, HVAC, and mechanical system applications — appearing at the equipment supply and secondary distribution tier of systems where 1-1/2-inch is the working pipe size at the specific non-return location. In commercial HVAC systems, 1-1/2-inch is a dominant individual equipment supply connection size across fan coil units, terminal heating and cooling equipment, and zone distribution connections. In commercial domestic water systems, 1-1/2-inch is the branch supply size that serves individual floor zones, fixture groups, and equipment connections that are too large for 1-inch supply but below the primary supply main size where 2-inch is specified. In steam systems, 1-1/2-inch branch connections at individual terminal heating units and process equipment connections are among the most numerous individual non-return valve locations in the complete system valve schedule.

The lead-free (NL) designation carries the same compliance significance for the 1105NL that it does for the 1106NL — confirming that the wetted surface brass alloy of the valve body, disc, and seat meets the federal Reduction of Lead in Drinking Water Act's weighted average 0.25% lead limit for potable water system components. For commercial plumbing contractors working on projects that require permit submission and inspection, the NL designation on the 1105NL is the code compliance confirmation that eliminates the material substitution documentation, variance requests, and inspection delays that non-compliant check valve specifications generate on commercial potable water system projects.

The threaded NPT end connections provide direct inline installation without welding or flange hardware, compact installation format appropriate for the secondary distribution and equipment supply connection locations where 1-1/2-inch check valves are most commonly installed, and future removal for inspection or replacement by unthreading from the pipe run without cutting or modifying the surrounding system piping.

Manufactured to the same lead-free brass construction standard as the 1106NL, the 1105NL completes the 1-1/2-inch position in the lead-free brass swing check valve series — providing the non-return protection specification for the secondary distribution and equipment connection tier of commercial and institutional piping systems where 1-1/2-inch is the working check valve size.

Specifications

Industries & Applications

The 1105NL is the lead-free brass swing check valve specification for 1-1/2-inch non-return backflow prevention across the full range of commercial, institutional, and light industrial water supply, HVAC, steam, and mechanical system applications:

• Commercial Domestic Water — Secondary Distribution & Zone Supply — Zone supply branch check valves on multi-zone commercial domestic water systems in office buildings, hotels, schools, hospitals, and multi-family residential buildings where 1-1/2-inch zone supply branches from 2-inch or larger primary distribution mains require non-return protection at the branch takeoff point; the 1105NL lead-free brass construction meets the potable water material compliance requirements of commercial plumbing permits and inspections at the secondary distribution check valve locations that are the most numerous individual check valve positions in large commercial domestic water systems.
• Booster Pump Discharge — Secondary Pump & Zone Pump Applications — Discharge non-return protection on 1-1/2-inch zone booster pumps, secondary circulation pumps, and small capacity booster pumps on commercial domestic water and HVAC hydronic systems where the check valve at pump discharge prevents back-spinning and reverse flow when the pump cycles off; the 1-1/2-inch size serves the secondary pump tier of multi-pump commercial systems where zone pumps and secondary boosters are sized at 1-1/2-inch discharge connections.
• HVAC Hydronic System — Zone & Equipment Non-Return — Non-return protection at zone supply connections, terminal equipment supply branches, heat exchanger inlet and outlet connections, and fan coil unit supply lines in commercial HVAC hydronic heating and cooling systems where 1-1/2-inch is the dominant individual zone and equipment supply connection size; prevents reverse flow through zone supply branches when zone pumps cycle off in variable flow systems and maintains zone hydraulic isolation in multi-zone hydronic distribution.
• Commercial Water Heater & Hot Water System — Cold water supply check valve on commercial water heater installations and hot water storage systems where a closed-system thermal expansion condition requires check valve isolation of the heater from the supply main; the 1-1/2-inch size serves commercial water heater installations where the supply connection is 1-1/2-inch, as well as hot water recirculation system check valve applications at the zone recirculation connection tier of large commercial hot water distribution systems.
• Steam Distribution Branch Non-Return — Non-return protection on 1-1/2-inch steam distribution branch connections, individual terminal heating unit supply lines, and steam-heated equipment supply connections where preventing steam and condensate backflow at branch connection points is required for system pressure stability and terminal equipment protection; confirm temperature and pressure ratings of the 1105NL against specific steam system operating conditions before specifying in steam service.
• Irrigation & Landscape — Commercial Supply Check — Non-return protection on commercial irrigation system supply connections and secondary distribution branches where preventing contaminated irrigation water backflow into the potable supply is both a code requirement and a system performance requirement; confirm whether the 1105NL's swing check design meets applicable code requirements for the specific backflow prevention application before specifying.
• Multi-Family Residential — Building Supply & Zone Check — Non-return protection on 1-1/2-inch building water supply connections, domestic hot water recirculation zone supply branches, and zone distribution check valve locations in multi-family residential buildings and apartment complexes where 1-1/2-inch is a primary zone and building supply connection size; lead-free NL compliance meets the potable water material requirements of residential building plumbing permits across all jurisdictions.
• Light Industrial Process Water Supply — Non-return protection on 1-1/2-inch process water supply connections, cooling water branch supply lines, and utility water distribution branches in light industrial facilities where the fluid chemistry and operating conditions are within the brass body compatibility range of the 1105NL; confirm chemical compatibility with the specific process fluid before specifying in non-standard water service.