Low pressure cutout switch

LOW-PRESSURE CUTOUT SWITCH The low-pressure cutout switch is also known as a suction pressure control switch. It is the control that causes the compressor to go on or off as required for normal operation of the refrigeration plant. This switch is connected to the suction side of the compressor and is actuated by pressure changes in the suction line. When the solenoid valves in the lines to the various evaporators are closed so that the flow of refrigerant to the evaporators is stopped, the pressure of the vapor in the compressor suction line drops quickly. When the suction pressure has dropped to the set pressure, the low-pressure cutout switch causes the compressor motor to stop. When the temperature in the refrigerated spaces has risen enough to operate one or more of the solenoid valves, refrigerant is again admitted to the cooling coils, and the compressor suction pressure builds up again. At the desired pressure, the low-pressure cutout switch closes, starting the compressor again and repeating the cycle. The oil pressure switch will have made contact to keep the compressor motor. -----------------------×××××××---------------------------------------------------------- MOHAMMAD IMRAN HVAC ENGINEER