Johnson Controls A-4000-121 Oil Indicator

The Johnson Controls A-4000-121 is a critical pneumatic oil indicator replacement cartridge designed for high-performance compressed air treatment in pneumatic control systems. As a veteran technician knows, maintaining oil-free air is non-negotiable for protecting sensitive downstream components like pressure reducing valves and actuators from fouling. This replacement cartridge is specifically engineered for use with the A-4000-120 oil indicator and the broader A-4000 series filter assemblies. It features a calibrated plastic tube containing a white material and a red oil-soluble dye; when oil aerosols or mists are present in the line, the dye travels up the tube to provide a precise visual readout of oil concentration. This OEM original part is essential for monitoring oil entrainment levels as low as 0.01 PPM, ensuring your HVAC pneumatic system operates within its 10 to 125 PSIG technical parameters without risk of contamination.

• Precise Detection: Accurately measures oil entrainment levels down to 0.01 PPM (0.012 mg/m3) to identify aerosol-mist contamination before it reaches critical controls.
• Application Specific: Direct replacement cartridge for the A-4000-120 series, ensuring exact fitment and maintaining the integrity of the needle valve assembly.
• Visual Monitoring: Reliable color-travel indicator provides an immediate status check of compressed air treatment efficiency.
• Wide Operating Range: Built to handle standard line pressures between 10 and 125 PSIG at temperatures up to 120°F.
• System Protection: Minimizes the risk of oil-related maintenance issues in pneumatic lines, extending the service life of Johnson Controls station assemblies.

When should the A-4000-121 cartridge be replaced?
Replacement is required whenever the red dye has traveled to the top of the tube or during scheduled annual maintenance of the A-4000 series filtration unit to ensure continuous monitoring accuracy.

Is this compatible with other pneumatic indicator brands?
This is an OEM original component designed specifically for Johnson Controls A-4000-120 indicators. Using it with non-compatible hardware can lead to inaccurate readings or air leaks at the needle valve fitting.

What causes the indicator to show high oil levels?
High oil readings typically indicate that the coalescing or activated charcoal filters in the A-4000 series station are saturated and require immediate replacement to restore air quality.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.