VG7241LS+3801D Johnson Controls Valve / Actuator

Overview

The Johnson Controls P28AA-1C is a lube oil pressure cutout control designed to provide dependable and economical oil pressure protection for pressure-lubricated refrigeration compressors. It measures net lube oil pressure (the difference between oil pump discharge pressure and compressor crankcase pressure) and de-energizes the compressor if the pressure falls below the differential setpoint, preventing potential system damage. This model features a built-in 90-second time delay switch that allows pressure to pick up upon startup and avoids nuisance shutdowns caused by short-duration pressure drops during the running cycle. It requires a manual reset that is trip-free, ensuring the system cannot be overridden or forced to run under unsafe conditions.

Features

• Built-in time delay relay with ambient temperature compensation to minimize timing fluctuations.
• Trip-free manual reset that cannot be overridden by holding down the reset button.
• Enclosed dust-protected Pennswitch unit for clean and reliable operation.
• Field-replaceable time delay relay assembly and terminal board.
• Direct-reading scale indication for clear visibility of pressure settings.

Specifications

• Model: P28AA-1C
• Adjustable Cut-out Pressure Difference: 8 to 70 psi
• Time Delay: 90 seconds
• Relay/Input Voltage: 120/240 VAC (50/60 Hz)
• Enclosure: NEMA 1
• Pressure Connection: 36-inch capillary with a 1/4-inch flare nut
• Switch Differential: Approximately 5 psig
• Maximum Bellows/Working Pressure: 180 psig (high side up to 250 psig)
• Maximum Overpressure: 325 psi
• Ambient Operating Temperature: 32°F to 104°F (0°C to 40°C)
• Factory Jumper: Not installed

Applications

• Designed primarily for pressure-lubricated refrigeration compressors, specifically semi-hermetic models.
• Ideal for environmental and commercial refrigeration monitoring systems utilizing non-corrosive refrigerants (such as R-12, R-22, R-134A, R-500, and R-502).
• Serves as a direct replacement option for legacy controls like the Ranco P30-3701.