Crankcase Heaters
A Crankcase Heater is an electrical component in a compressor in an air-conditioning system/ HVAC, heat pump system, or a chiller system. Crankcase heaters provide reliable peak heating during critical cold periods and, unlike conventional constant-wattage heaters, reduce their heating once the compressor starts up or the air temperature rises. This prolongs the life of the compressor, saving repair and replacement costs over time.
Common Problems
The following are the most typical problems in a system that can be resolved by the Crankcase Heater:
Liquid Refrigerant Migration
Within refrigeration and air conditioning systems, migration of liquid refrigerant to the compressor is a natural occurrence. The powerful affinity of oil for refrigerant is due to the difference in vapor pressures between the two fluids.
The amount and severity of this liquid refrigerant migration depends on several things, including refrigerant and oil charge, length of shutdown interval and, especially, the temperature difference between crankcase oil and the rest of the system. As the temperature of oil drops, refrigerant is absorbed faster and more completely.
Oil Slugging
When refrigerant has mixed with oil and the compressor starts, oil slugging occurs: the mixture foams violently and all or most of the oil charge is pumped out. The compressor tries to pump the liquid -- a feature for which it was never designed -- and broken valves, damaged pistons, and blown head gaskets can result.
Compressor Failure
In most compressors, the oil pickup is located at the bottom. From there, it is fed to the cylinders and bearings for lubrication. When refrigerant has migrated into the oil, the mixture stratifies, and refrigerant settles at the bottom.
Originally intended for lubrication, the contaminated oil can no longer do its job. Instead, the refrigerant's solvent properties cause severe damage, resulting in immediate (or eventual) compressor failure.
Benefits
By optimizing the temperature of crankcase oil, our crankcase heaters help protect the compressor from refrigerant migration. Oil is kept as much as 30° warmer than the system temperature and refrigerant is forced to remain in the condenser, evaporator or accumulator.
Crankcase heaters snugly clasps the compressor housing to provide positive, highly efficient transmission of heat. Acting as a heat sink, the crankcase can then absorb and transmit heat directly to the oil. Heat loss to ambient air is greatly reduced along with the major cause of refrigerant migration.
Videos