Watts LFU5B-LP-Z3 1/2 1/2 In Lead Free Water Pressure Reducing Valve, Npt Female Union X Npt Female, Low Range 10-35 psi

This is the low-range version, adjustable from 10 to 35 psi (0.7 to 2.4 bar). That makes it the one to use when you need a downstream pressure well below the usual 45 to 60 psi domestic setting, for example feeding low-pressure fixtures, filtration, or equipment with a low inlet limit. If you need 45 psi or more at the outlet, the standard-range version of the U5B is the right valve instead.

Both ends are 1/2 inch NPT female threaded, with the inlet side a female union connection. The union nut lets you break the valve out for service or replacement without cutting pipe or unthreading the whole run, which is why it is the common choice on a service line where you want the valve to come off in place.

It is a lead free valve with a lead free copper silicon alloy body and bronze trim, which is what puts it on potable water service rather than mechanical or irrigation-only duty. The wetted disc is EPDM and the body carries a corrosion resistant coating.

The LFU5B-LP-Z3 has a built-in thermal expansion bypass, so when downstream pressure from heater expansion rises above the supply pressure the valve relieves that back toward the street instead of trapping it. That is the feature that keeps a closed system from spiking. Whether an expansion tank is still required is a local code call for your jurisdiction, but the bypass is integral to this valve, not an add-on.

A stainless steel strainer is integral to the valve, so you do not need a separate inline strainer just to protect the seat. On dirty or older galvanized systems plan on being able to pull the strainer for cleaning, which is where the union inlet connection earns its keep.

No gauge is supplied with the LFU5B-LP-Z3 1/2. If you want to verify and dial in the reduced setting, you will need to add a gauge downstream, either a tee-mounted gauge or a Watts version of the U5B ordered with the gauge tapping.

Rated to 300 psi (20.7 bar) maximum working pressure and up to 180 F on the water side, with a minimum of 33 F (0.5 C). The 300 psi rating covers high city main pressure and tall-building risers; the 180 F ceiling means it will tolerate hot water service, so it can go on a recirculating or hot supply branch as well as cold.

The LFU5B-LP-Z3 1/2 is listed as Buy American Act compliant, USA. That is the line item procurement officers on federal, school, and municipal work ask for, so it can be specified on jobs carrying a domestic-content requirement.

Order model LFU5B-LP-Z3 1/2, Watts part number 9108, in the LFU5B-Z3 series. The LP in the designation is the low-pressure spring for the 10 to 35 psi range; a U5B without LP is the standard range and is not the same valve.