2" Brass Threaded Swing Check Valve (1106NL)

The 1106NL is a 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 at the check valve location is a system performance, equipment protection, or safety requirement — and where the lead-free (NL) brass construction meets the material compliance requirements of potable water systems under the federal Reduction of Lead in Drinking Water Act and applicable state and local plumbing codes that mandate lead-free wetted surface materials in potable water supply system components.

A swing check valve operates on a fundamentally simple and reliable mechanical principle — a hinged disc (the "clapper") that swings open under forward flow pressure and swings closed under its own weight and reverse flow pressure when forward flow stops or reverses. There are no external actuators, no power requirements, no control signals, and no operator intervention required for swing check valve operation — the valve responds automatically and immediately to flow direction changes in the piping system, opening to pass forward flow and closing to block reverse flow as a direct mechanical response to the pressure differential across the valve body. This automatic, passive operation makes the swing check valve the dominant backflow prevention specification for the broad range of general-purpose non-return applications where the simplicity, reliability, and low maintenance profile of the mechanical swing disc mechanism is more operationally appropriate than spring-loaded, ball-type, or actuated check valve alternatives.

The 2-inch diameter positions the 1106NL at the primary supply main and large-branch tier of commercial and light industrial water supply, steam distribution, and mechanical system piping — the size that appears at booster pump discharge connections, water heater supply and discharge check valve locations, steam system non-return points, pressure zone boundary isolation, and primary branch connections on commercial domestic water systems where 2-inch is the supply main or primary branch size. At this diameter, the swing check valve's full-bore flow path delivers the hydraulic performance — low head loss, full flow capacity, and low turbulence — that the 2-inch supply main applications it serves require at the flow rates and operating pressures of commercial water supply and steam distribution service.

The lead-free (NL) designation is a compliance-critical specification designation for the 1106NL that distinguishes it from standard brass check valves in the specific and legally significant context of potable water system applications. The federal Reduction of Lead in Drinking Water Act, enacted in 2011 and effective January 2014, restricts the lead content of wetted surfaces in plumbing products used in potable water applications to a weighted average of 0.25% lead — a threshold that eliminates standard free-machining brass (which typically contains 2–8% lead as a machining aid) from compliance and requires the lead-free brass alloys that the NL designation confirms. For commercial plumbing contractors, mechanical engineers, and municipal plumbing inspectors, the NL designation is the product specification confirmation that the 1106NL meets the federal and state lead-free requirements for potable water system installation without the material substitution documentation, variance requests, or code compliance uncertainty that non-compliant check valves generate on commercial and municipal plumbing projects.

Brass construction delivers the combination of corrosion resistance, machinability, pressure performance, and temperature capability that makes brass the dominant body material for threaded check valves in commercial water supply, steam, and general-purpose mechanical system applications — providing reliable service across the water supply conditions, steam pressures, and working fluid chemistries that define the 1106NL's application range, while the threaded NPT end connections allow direct inline installation and future removal without welding or flange hardware at the 2-inch diameter where NPT threading is practical and appropriate for the operating conditions the valve serves.

Specifications

Industries & Applications

The 1106NL is the lead-free brass swing check valve specification for 2-inch non-return backflow prevention across the full range of commercial, institutional, and light industrial water supply, steam, and mechanical system applications:

• Commercial Domestic Water Supply Systems — Booster pump discharge non-return protection on commercial domestic water supply systems where the check valve at pump discharge prevents back-spinning of the pump impeller and reverse flow through the pump body when the pump cycles off or loses prime; the 1106NL lead-free brass construction meets the potable water material compliance requirements of commercial building plumbing permits and mechanical system inspections on domestic water booster applications across office buildings, hotels, multi-family residential buildings, and institutional facilities.
• Water Heater & Hot Water System Protection — Cold water supply line check valve installation on commercial water heater systems and hot water storage systems where thermal expansion in a closed system creates reverse pressure on the supply line that can cause pressure relief valve weeping, pressure fluctuation, and temperature-pressure cycling issues without a check valve to isolate the heater from the supply main; the 2-inch 1106NL serves the primary supply connection tier of commercial water heater systems where 2-inch is the supply main size.
• Steam Distribution Non-Return Service — Non-return protection on steam distribution branch connections, boiler discharge lines, and steam system pressure zone boundaries where preventing steam and condensate backflow at branch connection points is required for system pressure stability and equipment protection; confirm temperature and pressure ratings against specific steam system operating conditions before specifying the 1106NL in steam service.
• Municipal & Commercial Plumbing — Pressure Zone Isolation — Pressure zone boundary non-return protection on municipal water distribution systems and large commercial domestic water systems where check valves at zone boundaries prevent cross-zone pressure equalization and maintain the pressure differential between distribution zones that the system design requires; lead-free brass construction meets municipal water system material specification requirements without material compliance documentation.
• Irrigation System Backflow Prevention — Non-return protection on commercial irrigation system supply connections, booster pump discharge lines, and chemical injection system supply headers where preventing contaminated irrigation water from flowing back into the potable supply is both a system performance requirement and a plumbing code requirement; confirm whether the 1106NL's swing check design meets the specific backflow prevention device requirements of the applicable code for the intended irrigation backflow prevention application.
• HVAC Hydronic System Non-Return — Non-return protection on hydronic heating and cooling system circulation pump discharge connections, heat exchanger supply connections, and system zone branch connections where preventing reverse flow through pumps, heat exchangers, and zone distribution branches when pumps cycle off is required for system hydraulic stability and equipment protection.
• Industrial Light-Duty Process Fluid Service — Non-return protection on light industrial process water supply connections, cooling water supply lines, and utility water distribution branches where the fluid chemistry and operating conditions are within the brass body and seat material compatibility range of the 1106NL; confirm chemical compatibility with the specific process fluid before specifying in non-water service applications.
• Fire Suppression System Supply Connections — Non-return protection on fire suppression system water supply connections where check valves are required to prevent backflow from the fire suppression system into the domestic water supply; confirm listing compliance and applicable NFPA and authority having jurisdiction requirements before specifying the 1106NL in fire suppression service.