Series-LF251

Supported Applications

The Weiss Series LF251 consists of 2.5" liquid-filled pressure gauges designed for general service conditions measuring pressure, vacuum, or compound ranges on air, oil, water, gas, and other media that do not attack brass. Documented applications include compressors & pumps, hydraulic equipment, plumbing & heating systems, and outdoor installations.

Operating Conditions & Performance

The series provides an accuracy of ±1.6% of span across a pressure rating up to 10,000 psi. Standard measurement ranges include positive pressures from 0/15 psi & kPa through 0/10,000 psi & kPa, as well as vacuum and compound configurations such as 30" Hg/0 and various combinations extending to 30"Hg/0/300 psi & kPa. Both ambient and process operating temperatures are specified at 0-140°F / -18-60°C.

Wetted materials vary by pressure range: Phosphor Bronze is used for ranges up to 6000 psi, while 316SS is utilized for ranges up to 10,000 psi. Brass components are present in the socket and movement. The gauge features a Type 304 stainless steel housing with glycerine fill.

Configuration Options

The Series LF251 is configurable across multiple dimensions to accommodate specific installation needs:

• Ranges and Scales: Available in standard pressure ranges (0/15 through 0/10,000 psi & kPa) and vacuum/compound scales. Dial markings are offered in PSI ONLY, PSI & BAR, or PSI & kg/cm2.
• Process Connections: Standard connections include 1/4 NPT bottom (code 4L) or center back (code 4B). SAE Thread options (7/16"-20 w/ o-ring, washer & nut) are available as an option.
• Housing and Mounting: The standard configuration includes a stainless steel case. Optional mounting accessories include the Series LF251U U-CLAMP and Series LF251F FRONT FLANGE.
• Liquid Fill Options: Silicone Liquid Fill is available as an option in addition to the standard glycerine fill.
• Special Service Configurations: Lead-Free Brass Internals for Potable Water and Custom Dial Markings are offered. Blister Packaging is also available.

Key Product Differences

The series distinguishes between pressure-only, vacuum-only (30" Hg/0), and compound ranges (e.g., 30"Hg/0/15 psi & kPa). Model numbers follow the format LF251 - <Range Code> - <Connection Code>, where connection codes denote orientation: "4L" indicates a 1/4 NPT Lower (bottom) mount, and "4B" indicates a 1/4 NPT Back (center back) mount. Wetted material composition changes based on the selected pressure range code, with Phosphor Bronze specified for ranges up to 6000 psi and 316SS required for higher pressures.