The recent COVID-19 pandemic forced many businesses to shut down for an unknown period of time. These long shutdowns can wreak havoc on refrigeration and air conditioning systems if certain steps are not taken in either properly shutting down or starting up the equipment once the shutdown is over.
During a long shutdown, the system’s refrigerant will want to travel, or migrate, to a place where the pressure is the lowest within the refrigeration or air conditioning system. Refrigerant migration is defined as refrigerant, either liquid or vapor, traveling to the compressor’s suction line or crankcase during an off cycle. Fluids travel from a place of higher pressure to a place of lower pressure. Even though the crankcase and evaporator are both in the low-pressure side of the system, the crankcase usually has a bit lower pressure than the evaporator because of the system’s lubrication oil it contains.