During the heat pump defrost cycle, how is the cooling cycle modified?

During the heat pump defrost cycle, the outdoor fan is temporarily shut off to facilitate the defrost process. When ice accumulates on the outdoor coil, it can hinder the efficiency of the heat pump's operation. By turning off the outdoor fan during this cycle, the heat pump can redirect warm refrigerant from the indoor coil to the outdoor coil, melting the ice and allowing for improved heat exchange once the defrost cycle is complete.

This approach is essential for maintaining efficiency and performance, as it allows the system to control the temperature of the refrigerant more effectively without the cooling effect generated by the outdoor fan. Other components of the system, like the compressor, may operate at reduced capacity during this time, but the primary action here involves managing airflow through the outdoor unit by stopping the fan. This ensures that the ice melts quickly without additional cooling from the fan, ultimately helping to restore the heat pump's functionality for effective heating.