Common Freezing Issues on Outdoor Units

by / Tuesday, 09 June 2015 / Published in Industry Findings

Freezing or Icing Over of outdoor units during different weather scenarios are a common occurrence. Below we have shared a few reasons as to why this may be happening to your unit.

The Issue

Can Icing of an outdoor unit be caused by the system being oversized for the space?   I have a system that ices up the outdoor unit from time to time and the load is about 9K on an 18K BTU unit.  The icing has occurred when it is heating mode.  Heat loss for the building is about 14K, but I am sure that is worst case weather.  Icing has occurred when outside temps are more moderate.

An Explanation

Although the load and size of the unit does matter, with inverter technology it becomes less of an issue (unless tremendously oversized, meaning the lowest turn down is not low enough).

The freezing issues on outdoor units are more commonly caused by:

  • Leaking gutter or rain/snow falling and getting into contact with condenser coils.
  • Unit mounted on north facade with cold winds and prevailing strong breezes + no sunlight.
  • Unit not properly elevated
  • Coils dirty and filled with debris, like leaves, etc
  • Unit mounted near ocean/lake or high humidity source.
  • An excessively high temp setting for the indoor unit when outdoor temperature is low, and in addition the defrost mode should be working.
TOP