Overview
The Lonergan D-12HS122-LF relief valve is a direct spring-operated pressure relief valve designed for industrial applications requiring stable pressure control. With a 1-1/2″ inlet and 3″ outlet, this valve delivers dependable performance in fluid power systems, boiler systems, compressors, and hydraulic circuits. Built with a carbon steel body, bonnet, and alloy steel spring, the D-12HS122-LF meets the durability demands of heavy industrial use.
Key Features
- Direct spring-operated design for simple, reliable pressure relief operation
- 100 PSIG factory set pressure with field adjustment capability
- Flanged inlet/outlet connections (Class 150 standard)
- Carbon steel body and bonnet construction for extended service life
- Compact footprint suitable for confined spaces in equipment mounting
Technical Specifications
The following specifications are extracted from the part number and typical Lonergan D-series valve characteristics:
Typical Applications
The Lonergan D-12HS122-LF relief valve is suitable for:
- Industrial steam and hot water systems
- Hydraulic power units and machinery
- Compressed air distribution networks
- Boiler safety and pressure regulation
- Process equipment overpressure protection
Compatibility & Replacements
Compatible With
- Direct spring-operated relief valve systems
- Flanged Class 150 inlet/outlet connections
- Fluid systems operating at 100 PSIG or below
- Industrial pressure vessels and equipment requiring ASME compliance
Replaces / Drop-In Replacement For
The Lonergan D-12HS122-LF is compatible with other legacy Lonergan H-series valve configurations. Verify compatibility with your system integrator or equipment manufacturer before ordering, as relief valve replacements must match set pressure, flow capacity, and connection size exactly.
Works With
- ASME Section VIII pressure vessel systems
- Class 150 flanged piping networks
- Industrial steam, water, air, and light hydrocarbon fluids
- Manual overpressure protection systems












































