My Brand New Air Conditioner Isn't Cooling

Settings

• If you call out an HVAC repair technician, the first thing he will check for is user error. Check this out yourself by looking at the settings on the controls. Make sure they are all in the correct position. Set the unit to "cool" instead of "heat" or "off." Make sure the thermostat is set to a temperature that is lower than the ambient temperature in the house. If either of these settings is wrong, then it will result in an air conditioner that blows warm air or does not blow at all. This is a simple fix and is a common error by those who are not used to dealing with an air conditioner.

Wrong Location of Thermostat

• Where the installer positions the thermostat on a central air conditioning unit is more important than you might think. The thermostat's position may prevent your system from maintaining the desired temperature in your home. The thermostat could be in a place where an air vent blows directly on it, cooling it quickly below the desired temperature setting. This causes the thermostat to send a signal to shut off the system. The result is a home that isn't as cool as you want. The opposite is true of thermostats located in the direct sunlight during part of the day. The radiant heat makes the thermostat hotter than the rest of the house and may force it to turn on the system, which will cool continuously and make the house too cold. The thermostat should be in a spot away from vents and out of the sunlight.

Blocked or Frozen Condenser

• An air conditioner will stop cooling properly when its condenser coil freezes up. The flow of air is restricted during these times, making for inefficient cooling. The reason condenser coils freeze may be because of low refrigerant charge -- which may indicate a leak. Debris or tall grass hindering the air flow around the unit intakes could also lead to excessive frost and freezing, which result in the same lack of cooling. If you see that your condenser coil is frozen, get the installer back out to check for leaks and refrigerant level and clear away any debris from around the outside unit.

Registers and Ducts

• Once the air conditioner makes cool air, it must deliver it throughout the home using a system of ducts and out through registers or vents. If the ducts were not properly installed and the cool air is leaking from them before entering the home it can drastically affect cooling. Also, if the registers are in a closed position the air cannot get into the house. Check your ducts for air leaks and make sure your registers are all open completely to maximize cooling.