Watts 0009108 1/2 In Lead Free Water Pressure Reducing Valve, Npt Female Union X Npt Female, Low Range 10-35 psi

Both ends are 1/2 inch female NPT, so it threads onto 1/2 inch male NPT nipples or adapters at both inlet and outlet. The inlet side is a union connection, so you can break the valve out for service without cutting pipe or unthreading the downstream run. On copper, you'll need male adapters soldered or pressed onto the tube.

The body is a lead free copper silicon alloy with bronze trim and an EPDM seat disc, which is the construction Watts uses for its LF potable water line. It is listed for both commercial and residential service, so it suits domestic water supply rather than being limited to mechanical or non-potable use.

The 0009108 has a built-in thermal expansion bypass, so when downstream pressure rises above inlet pressure (the usual case when a water heater fires against a closed valve), it allows the excess back through toward the supply instead of dead-ending it. That handles thermal expansion where the street side can accept it. On a system with a backflow preventer or check upstream, the bypass has nowhere to relieve to and you still need an expansion tank.

A stainless steel strainer is integral to the valve, so no separate Y-strainer is required upstream just to protect the seat. Stainless resists the corrosion and clogging you get from a plated screen on well or older galvanized systems, and it can be pulled and rinsed during service.

No gauge is supplied with this one. If you need to dial in a setting inside the 10 to 35 psi band, plan on a gauge on a tee downstream or order a gauge-equipped version of the valve. Without one you're setting blind, which matters more on a low range valve than on a standard house PRV.

Maximum working pressure is 300 psi (20.7 bar), which covers high-rise risers and well systems with aggressive pump cut-out settings. Temperature range runs from 33F (0.5C) up to 180F (82C), so it is fine on cold domestic supply and on tempered or recirculated hot water lines below 180F. It is not a valve for steam or for boiler water above that limit.

Construction is aimed at that environment: a lead free copper silicon alloy body with a corrosion resistant coating, bronze internal trim, and a stainless strainer screen rather than a plated one. The EPDM disc is the standard seat elastomer for domestic water service. For a like-for-like swap you also need the old valve to be 1/2 inch NPT on both sides and the new setpoint to fall inside 10 to 35 psi.

Order Watts 0009108, model 9108, series LFU5B-Z3. That designation is the 1/2 inch lead free water pressure reducing valve with NPT female union inlet by NPT female outlet, low range 10 to 35 psi, no gauge.