What is the intended purpose of a defrost cycle in a heat pump?

The primary purpose of a defrost cycle in a heat pump is to remove frost buildup on the outdoor coil during cold weather operation. When the temperature drops, moisture in the air can freeze on the outdoor coil, which impedes airflow and reduces the efficiency of the heat pump. The defrost cycle temporarily reverses the refrigeration cycle, causing the system to operate in cooling mode, which heats the outdoor coil and melts the accumulated frost.

This process is crucial because an ice-covered coil would not only hinder the heat pump's ability to effectively extract heat from the outside air but could also lead to potential damage to the system if the frost is allowed to build up excessively. Therefore, enabling the heat pump to defrost ensures it maintains its heating capabilities even under challenging winter conditions.