When your furnace is in the heating mode, this will restrict air flow through the furnace and cause it to overheat and shut down. It will come back on after it cools down, but may not provide enough heat to keep the house warm. In the cooling mode it will restrict airflow through the evaporator coil and cause the coil to ice over and block the flow of air. You may see ice forming on the refrigerant tubing by the a-coil or the outside unit when this happens. The result will be poor cooling at first, then no cooling at all when the a-coil is totally covered with ice.

 

Filters should be changed or cleaned regularly to prevent this problem. Some one-inch pleated filters can be too restrictive even when they are brand new and clean. Call us at 630 718-2700 for recommendations on high efficiency filters.

 

Make sure return grills are not blocked and most supply registers are left open for your furnace or air conditioning adequate air flow. Your furnace and air conditioning units could suffer permanent damage when allowed to run with poor air flow.