Zurn Wilkins - NR3 XL - Direct Acting Type Pressure Reducing Valve

The NR3 Pressure Reducing Valves are ideal for residential applications that require frequent cleaning of sediment and debris to prevent buildup to protect commercial and residential plumbing systems. The NR3 PRV’s stainless steel strainer screen catches sediment and debris without buildup to protect your plumbing system, while the cartridge design ensures easy repairs. This PRV features a corrosion-resistant, threaded bell construction for rapid access to the internals to speed up maintenance. Building owners experience lower costs and fewer repairs over the product's lifespan.

Features and Benefits

• Bronze and composite construction reduces electrolytic corrosion. Electrolytic corrosion occurs when two dissimilar metals are joined and react to each other. XL models are constructed of lead-free bronze and contain a weighted average lead content of less than 0.25% for wetted surfaces.
• Threaded bell provides easy access to the spring, diaphragm, screen or plunger for service and maintenance. Eliminates screws that can corrode.
• Hex on bell provides greater repair access without removing screws and without special tools.
• The stainless steel screen is durable and corrosion-resistant, eliminating debris that causes fouling.
• Nylon-reinforced Buna-N diaphragm provides superior strength.
• Stainless steel or composite seat is durable and corrosion resistant, reducing the potential for wire draw.
• Patented O-ring bypass prevents a pressure buildup from thermal expansion.
• Union connections are available on all Zurn Wilkins PRVs up to 2 in., allowing greater installation versatility. Double unions, PEX, copper sweat, NPT, CPVC, and solderless connections are available.
• Full approval set includes ASSE, cUPC, CSA, and more.
• Z-Bite™ and Z-Press™ solderless connections are available in union tailpiece connections and integral fittings for easy installation.
• Orientation can be installed in any position. Common approved installation positions include single PRV, sealed cage/pit installation, PRVs in series, and PRVs in parallel.
• Sealed cage available for below-grade applications with corrosive environments

Typical Application

Ideal for use where Lead-Free* valves are required. Designed for installation on potable water lines to reduce high inlet pressure to a lower outlet pressure. The integral strainer makes this device most suitable for residential and commercial water systems that require frequent cleaning of sediment and debris. The direct-acting integral by-pass design prevents the build-up of excessive system pressure caused by thermal expansion. The balance piston design enables the regulator to react in a smooth and responsive manner to changes in system flow demand, while at the same time, providing protection from inlet pressure changes. The sealed cage washer and stainless steel adjustment bolt and nut improve corrosion resistance for all applications including below-ground pit installation.

Standards Compliance

• Australian Watermark Approved WM-001965

Operation

Zurn Wilkins direct-acting pressure reducing valves are normally open and are biased to the open position by a preloaded spring (1). The valve will remain in the open position until downstream pressure forces the plunger (2) onto the seat (3), closing the valve. The valve is closed by reduced pressure water pushing on the wetted side of the diaphragm (4), countering the force of the spring (1). The amount of reduced pressure is directly proportional to the preloaded spring (1). When the valve is pressurized, it remains closed until downstream demand is placed on the system. When demand occurs, such as turning on a faucet, the outlet pressure drops and decreases the force on the wetted side of the diaphragm (4), allowing the spring (1) to bias the valve open to satisfy demand. The valve will continue to modulate in the open position until the demand placed on the system ceases. When demand ceases, the valve will close. Pressure reducing valves are capable of holding the static downstream pressure within very narrow limits, because the operating intelligence for PRVs is independent of inlet pressure, regardless of inlet pressure fluctuations

Intergral Bypass

The pressure downstream of a PRV can build from thermal expansion or the use of pumps. When downstream pressure builds and exceeds inlet pressure, an integral bypass bleeds off excess pressure by allowing water to flow upstream through the bypass, limiting pressure built in a system to that of the inlet pressure. With an integral bypass, pressure in a system will never exceed that of the inlet pressure if there is no backflow prevention device installed. Excess downstream pressure can cause a temperature and pressure relief valve (T&P valve) installed on the hot water heater to open when system pressure exceeds the T&P valve set point (typically 150 psi). T&P valves are safety devices designed to operate a limited number of times in emergency situations only. An integral bypass will keep pressure from rising to the T&P opening point if the inlet pressure is less than 150 psi. All Zurn Wilkins PRVs have integral bypasses that operate by using an O-ring in a conic O-ring gland (5). Under normal conditions, where water pressure coming into the PRV is greater than the downstream pressure, the O-ring is pushed into the narrow section of the gland by incoming pressure and seals tight. In the event that the pressure on the downstream side of the regulator becomes equal to the incoming pressure, the O-ring will slide to the wide section of the gland to unseal, opening the bypass. If a backflow preventer is present, or if the inlet pressure is excessive, a pressure relief valve or thermal expansion tank (Zurn Wilkins XT series) should be installed downstream of the PRV to address thermal expansion

Operating Parameters

NR3 - sizes (15-32mm)

• Max. Working Water Pressure: 2700kPa
• Max. Working Temperature: 60° Celsius
• Reduced Pressure Range: 100-515kPa
• Factory Preset: 350kPa or 500kPa
• Maximum Reduction: 4 to 1

NR3 - sizes (40 & 50mm)

• Max. Working Water Pressure: 2100kPa
• Max. Working Temperature: 60° Celsius
• Reduced Pressure Range: 170-515kPa
• Factory Preset: 350kPa or 500kPa
• Maximum Reduction: 4 to 1

Materials

• Main Valve Body: Cast Bronze
• Bell Housing: UV Res. Polymer Composite
• Internals: Stainless Steel
• Stem: Brass
• Elastomers: Buna Nitrile, EPDM
• Cartridge: DelrinTM
• Strainer Screen: Stainless Steel
• Springs: Stainless Steel

Flow Characteristics

MODEL NR3 15mm, 20mm, 25mm

MODEL NR3 40mm, 50mm

Dimensions and Weights