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Air Conditioning: The Effects Of An Undersized Return Air Duct System

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The return air duct system is responsible for guiding air from the building to the air conditioning system. Therefore, if the system's return air openings are too small or too few in number to allow enough air to get into the air conditioning system, they will have a negative effect on the air conditioner's performance. Return air ducts that are way narrower than the blower fan's opening will also have the same effect. The following are the most common effects of an undersized return air duct system.

A reduction in the air conditioner's cooling efficiency

An undersized return air duct system simply starves the air conditioner. It limits the availability of warm air. This includes warm air availability in the evaporator coil area. This is a problem, since adequate warm air supply to the evaporator coil is necessary to keep it ice-free. Therefore, without the warming effect that an adequate supply of warm air usually guarantees, the temperatures in the coil will drop to levels that trigger both condensation and freezing. As a results, layers of ice will form on the coils, insulating the coils. Any air that passes over the coils will thereafter have a hard time getting cooled—something that eventually reduces the effectiveness of the air conditioner as far as cooling a home is concerned.

An increase in air conditioner water leaks

In addition to reducing the air conditioner's ability to cool a home, the ice that forms over the coils will allow the evaporator coils to hold more water than they normally would. This is because the condensate drainage system can only handle the condensate when it is in liquid form and so any condensate that freezes due to airflow-caused temperature drops will remain in the system. This accumulation will go on right until an increase in environmental temperature forces the ice to melt. When this happens, all the stored water will be released at once. This onrush of water isn't something that the air conditioner's condensate drainage system is designed to handle. The water will therefore not only fill the condensate collector tray, but also overflow. This is what will then lead to an increase in incidences of air conditioner water leaks.

To prevent these airflow-caused problems, increase the number of your air conditioner's return air inlets. And if the diameter of your return air ducts is significantly less than that of the blower's opening, replace the ducts will larger ones. Doing this will increase the amount of air supplied to your system and will go a long way towards restoring your system's performance. For more information, contact a company like Jess Kerley Heating and Air Electrical.


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