Lube Oil Controls

Protect compressors from damage with controls that detect a drop in the pressure available to circulate oil through the lubrication system.


P545 Series

P545 Series electronic lube oil controls are used for refrigeration compressors whose oil pump accepts a single-point differential pressure switch. The P400 switch continuously monitors net lube oil pressure, and the P545 control locks out the compressor if lube oil pressure falls below the manufacturer's recommended net pressure for longer than the recommended lube oil time delay. Front-mount LEDs indicate lubrication system status, and a user-selectable, minimum-off time delay can be set to minimize compressor short cycling.



P12 Series

P12 Series differential pressure controls can be used with oil and non-corrosive refrigerants. The switch is actuated by a difference in pressure between the two sensing elements. Connect this control to a P28 Lube Oil Control, with time delay, to monitor lubrication on two refrigeration compressors driven by one motor.


P28 Series

P28 Series cutout controls measure the pressure available to circulate oil through a refrigeration compressor’s lubrication system. A built-in time delay switch, compensated for ambient temperature, enables pressure pickup on start, avoiding nuisance shutdowns on short-duration pressure drops during the running cycle. Use for semi-hermetic compressors.



P29NC is a low pressure control with time delay and lockout, and requires manual reset. A drop in pressure energizes the time delay relay, which then opens a contact and shuts down equipment. The time delay prevents nuisance shutdowns due to momentary fluctuations in system pressures.


P45 controls

P45 controls protect semi-hermetic refrigeration compressors by detecting low lube oil pressure. The low-adjustable factory-set pressure setting supports operation at the compressor manufacturer’s specification. A built-in time delay relay, compensated for ambient temperature, enables pressure pickup on start, avoiding nuisance shutdowns on short-duration pressure losses.


P74 Series

P74 Series controls measure the pressure difference between supply lines and return lines. A change in differential pressure repositions the switching mechanism, causing corrective action. Use with chillers, water-cooled condensers, refrigeration compressors, and motor-actuated valves.


P128 and P145 Series

P128 and P145 Series controls provide dependable low pressure lube oil cutout for pressure-lubricated refrigeration compressors. P128 controls offer adjustable range settings. P145 controls are factory-set to compressor manufacturer’s specifications. Use for lube oil cutout on hermetic and semi-hermetic compressors in commercial air conditioning and commercial and industrial refrigeration systems.


To learn more about our entire line of compressor lube oil controls, ask your friendly, experienced PENN team.