Johnson Controls P45NAA-5 Cutout Control

The Johnson Controls P45NAA-5 is a professional-grade oil pressure cutout control designed to provide critical protection for pressure-lubricated refrigeration compressors. Featuring a 120-second time delay, this electromechanical switch prevents nuisance shutdowns during initial startup or brief pressure fluctuations while ensuring the system de-energizes if safe net oil pressure is not maintained. This unit operates on 24 Vac/Vdc and is compatible with all non-corrosive refrigerants, making it a versatile choice for commercial HVACR refrigeration units. Engineered to monitor the differential between oil pump pressure and crankcase pressure, the P45NAA-5 ensures your semi-hermetic compressor operates within manufacturer specifications. This model includes a manual reset mechanism to ensure a technician inspects the system before restarting after a low-pressure fault. It serves as the direct replacement for S1-025-29003-000 and is interchangeable with most Penn P28 and P128 series controls, simplifying field retrofits and maintenance tasks.

• Universal Application: Compatible with all standard non-corrosive refrigerants across a 7 to 60 PSI range.
• Ambient Compensation: The built-in thermal time delay provides consistent timing regardless of ambient temperature variations at the control location.
• Direct Cross-Reference: Specified as the primary replacement for York S1-025-29003-000, reducing downtime during part sourcing.
• Trip-Free Manual Reset: Internal pressure-actuated contacts remain locked out until manually addressed, protecting the compressor from repeated low-lube cycles.
• Rugged Reliability: Features proven sensing elements and a bellows design capable of withstanding up to 425 psig maximum pressure.

How do I calculate net oil pressure for this control?
Net oil pressure is determined by subtracting the suction (crankcase) pressure from the oil pump discharge pressure. The P45NAA-5 monitors this differential to ensure the lubrication system is active.

Can this control be used on 120V or 240V systems?
As a 24 Vac/Vdc model, this specific unit is designed for low-voltage pilot circuits. For high-voltage applications, ensure you are utilizing the correct heater circuit or an external step-down transformer as per the wiring diagram.

What refrigerant types are compatible?
This control is rated for use with all non-corrosive refrigerants, including common HFC, HCFC, and CFC blends typically found in commercial refrigeration and HVAC systems.

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.