A crankcase heater keeps the compressor crankcase warm during the off cycle so refrigerant does not migrate and condense in the oil, which protects the compressor from a flooded start. Enertech installation literature states that a crankcase heater is required when the line-set equivalent length is 50 feet or more, or when there is 20 feet of vertical separation between the compressor section and the air handler.

Enertech identifies 48P001-01NN as the crankcase heater for model sizes 018-036; the companion part 48P002-01NN covers sizes 048-072. This unit is rated 40 watts at 240 volts and is supplied with 21.75" leads.