Johnson Controls A-4000-120 Oil Indicator with Needle Valve for Compressed Air Systems

The Johnson Controls A-4000-120 is a calibrated measuring instrument designed to detect aerosol-mist levels of oil entrainment in compressed air systems. This precision indicator is sensitive enough to measure oil concentrations as low as 0.01 PPM (0.012 mg/m³) and operates with line pressures between 10 and 125 PSIG (70 and 875 kPa).

How It Works:

Oil present in the air carries a red oil-soluble dye up a tube, coloring a white material inside at a rate proportional to the amount of oil present. A conversion chart is included to determine the parts per million (PPM) value of oil entrainment indicated on the cartridge.

Key Features:

• Detects oil contamination in compressed air lines
• Visual color indication for easy monitoring
• Integrated needle valve for controlled sampling
• Suitable for quality control testing of compressors and air filtration systems
• Includes conversion chart for accurate PPM readings
• Replaceable cartridge system for repeated use

This oil indicator is ideal for maintenance professionals who need to verify air quality, check for compressor oil carryover, or monitor filtered air supply sources. The needle valve allows the unit to remain installed in the line between tests, with cartridges easily removed and replaced as needed.