GCAP Book Practice Test

The compressor is the component that directly provides the high-pressure gas during hot gas defrost. In the refrigeration cycle, the compressor's role is to compress the refrigerant gas, increasing its pressure and temperature. When hot gas defrost is initiated, the compressor pumps the high-pressure, heated refrigerant gas from the discharge line into the system, typically bypassing the expansion valve. This high-pressure gas then flows through the evaporator coil, where it releases its heat, thereby melting any frost that has built up.

Understanding the function of each component highlights why the compressor is vital for this process, as only it has the capability to convert low-pressure gas into high-pressure gas suitable for the hot gas defrosting method. The evaporator coil, expansion valve, and condenser, while integral to the overall refrigeration cycle, do not create or provide the high-pressure gas needed for defrosting.