Johnson Controls P128AA-1 Oil Control

The Johnson Controls P128AA-1 is a commercial-grade Lube Oil Control designed for pressure-lubricated refrigeration compressors. This control measures the net oil pressure difference and utilizes a 90-second time delay heater to prevent nuisance shutdowns while protecting the compressor from catastrophic failure due to lubrication loss. Featuring a wide adjustable cut-out pressure difference ranging from 8 to 70 PSI, it provides flexibility for various system requirements. The unit is equipped with 1/4" SAE flare connectors and lacks capillary tubing, reducing potential leak points in the field. Built for durability with dual voltage 120/240 VAC capability, it is compatible with all non-corrosive refrigerants. This model serves as a direct replacement for P28AA-45, P28AA-41, and P28DA-1 (note: replacing P28DA-1 requires two units). Ensuring precise oil pressure safety switch operation, the P128AA-1 includes a manual reset button for technician verification following a trip condition.

Key Benefits

• Precise Pressure Differential: Adjustable 8-70 PSI range allows for fine-tuning based on specific compressor manufacturer requirements.
• Universal Refrigerant Compatibility: Engineered for use with all non-corrosive refrigerants commonly found in commercial HVACR applications.
• Enhanced Reliable Connectivity: 1/4" SAE flare fittings offer a secure connection without the fragility of traditional capillary tubes.
• Time Delay Protection: Integrated 90-second delay prevents short-cycling and allows for pressure stabilization during startup.
• Direct Retrofit Capability: Streamlined installation when replacing legacy P28 series controls in existing mechanical systems.

Common Questions

How do I wire the P128AA-1 for 240V vs 120V circuits?
The unit features multi-tap terminal configurations; refer to the internal wiring diagram to ensure the heater circuit is matched to the control voltage to maintain accurate timing.

Is this control compatible with ammonia systems?
No, this model is designed for non-corrosive refrigerants. For ammonia applications, a stainless steel bellows or compatible separator is required.

Can the 90-second time delay be field-adjusted?
Standard P128 series time delays are factory-set at 90 seconds to meet most manufacturer lubrication specifications and are not adjustable in the field.

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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.