Why is it important for the runoff from the defrost cycle to drain away from the outdoor coil?

The importance of having the runoff from the defrost cycle drain away from the outdoor coil primarily relates to the prevention of excessive ice buildup. When the heat pump enters the defrost cycle, it temporarily reverses the refrigeration process to melt any frost or ice that has accumulated on the outdoor coil. If this water runoff is not properly drained and instead pools around the unit, it can refreeze and create a layer of ice.

This excessive ice buildup can significantly reduce the efficiency and capacity of the heat pump. A heat pump relies on the outdoor coil to absorb heat from the air, and if ice or frost obstructs this coil, it cannot effectively perform its function. This not only hampers heating capacity but can also lead to operational issues and increased energy costs as the system works harder to maintain comfort levels. Ultimately, ensuring adequate drainage during the defrost cycle is vital for the overall performance and longevity of the heat pump system.