Johnson Controls P28DN-4 Lube Oil Control

The Johnson Controls P28DN-4 Lube Oil Control is a heavy-duty oil pressure safety switch engineered to protect refrigeration and HVAC compressors from catastrophic damage caused by low lubrication pressure. This dual-voltage control operates on 120/240 Vac and features a precise adjustable cut-out pressure difference ranging from 8 to 70 PSIG. Designed for high-pressure environments, it maintains a maximum working pressure of 250 PSIG and a peak overpressure rating of 325 PSI. To prevent nuisance tripping during initial startup or temporary fluctuations, the P28DN-4 incorporates a 30-second time delay heater. If oil pressure does not rise above the setpoint within this window, the unit locks out, requiring a manual reset to restart the system. This model serves as the direct replacement for P28DN-4C, P28DN-5, P28AN-1, P28AN-15, and P28AN-6, ensuring seamless integration into existing commercial cooling and industrial compressor circuits.

• Direct Compatibility: Replaces multiple legacy P28 series models, reducing inventory needs and simplifying field service.
• Enhanced System Safety: The manual reset lockout ensures a technician inspects the oil levels and lubrication circuit before the compressor can be re-energized.
• False Trip Mitigation: A built-in 30-second thermal time delay allows for normal pressure stabilization during compressor startup cycles.
• Versatile Application: Adjustable differential settings from 8 to 70 PSI allow for fine-tuning based on specific compressor manufacturer requirements.
• Alarm Integration: Equipped with dedicated alarm terminals to provide remote notification of a lubrication failure.

What is the difference between the P28 and P70 series?
The P28 series is specifically designed as a time-delayed lube oil pressure switch that measures the net oil pressure (oil pump discharge minus crankcase pressure), whereas most P70 controls are standard pressure regulators or high/low limit switches.

How do I wire the P28DN-4 for different voltages?
This control features universal wiring capability for 120V or 240V circuits. Always reference the terminal markings to ensure proper heater circuit connection for the 30-second delay function.

Can this control be used with all refrigerants?
The P28DN-4 is compatible with non-corrosive refrigerants. For ammonia applications, a specialized version with different bellows material would be required.

This item is not eligible for free shipping.

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.