PENN COMMERCIAL REFRIGERATION
PRESSURE CONTROLS
ADJUSTABLE OIL PROTECTION SWITCH
P28
OIL PROTECTION
These controls measure the pressure differential between the pressure generated by the oil pump and the refrigerant pressure at the crankcase .
A built-in time delay switch allows for pressure-pick up on start and avoids nuisance shutdowns on pressure drops of short duration during the running cycle . When the compressor is started , the time delay switch is energised . If the net oil pressure does not build up within the required time limit , the time delay switch trips to stop the compressor . If the net oil pressure rises within the required time after the compressor starts , the time delay switch is automatically de-energised and the compressor continues to operate normally . If the net oil pressure should drop below setting ( scale pointer ) during the running cycle , the time delay switch is energised and , unless the net oil pressure returns to cut-in point within the time delay period , the compressor will be shut down , and have to be manual reset .
The compressor can never run longer than the predetermined time on low oil pressure . Controls are available only for manual reset after cut-out .
FEATURES
• Heavy duty pressure elements
• Safety lock-out with trip-free manual reset
• Ambient compensated timing
• Dust-tight Penn switch
• Wetted materials approved for use with standard and ( mild ) flammable A2L / A3 refrigerants
APPLICATION
These oil protection controls are designed to give protection against low net lube oil pressure on pressure lubricated refrigeration compressors .
DIMENSIONS ( in mm )
Style 5 Style 13 Style 15
54 - REFRIGERATION
European Products Catalogue 2021