Your AC Is Not Cooling

There are 5 possible reasons your air conditioning and/or heat pump system is not putting out cool air into your house.

Improper Air Flow

Things that can impede the air flow are:

1. Dirt/Dust/Pet Hair/Debris clogging that cooling coil
2. Dirty filter(s) that are preventing the air from getting to the cooling evaporator coil
3. Ice is covering or partially covering the evaporating coil

Condenser Not Transferring Heat to the Outside Air

Without enough outside air flowing over the surface of the condenser coils, it becomes increasingly difficult to remove the heat at the condenser. This means the compressor has to work for a longer time with increasing pressures and raising the temperature in order to get the refrigerant to condense back to a liquid.

This may occur in the following circumstances:

1. There is something blocking the condenser unit such as plants, shrubs or some other obstruction to air flow.
2. The condenser coils are dirty or clogged, possibly with grass clippings, dirt, leaves or other plant litter.
3. The condenser unit fan is not working.

Problem with the Thermostat

While the thermostat may not be working and may need to be replaced, often the problem is that the thermostat is just not set correctly.

1. Make certain that the thermostat indicates that the system is on and set to the cooling or Air Conditioning mode.
2. If you cannot feel cool air coming from the ducts, it may be that the fan is set to “Run” or “On” instead of “Auto”. When the fan is on Auto or automatic setting, the fan will turn on only after the cooling cycle has started, and will shut off once the set temperature is reached. If the fan is set to “Run” or “On” the fan will run continuously whether the air is cool or warm.

Low or Leaking Refrigerant

If the level of refrigerant in your heat pump or air conditioning unit is not sufficient, it will take longer to cool your space. When this happens, the condensation on the coils can freeze, and reduce or eliminate the air flow that can be in direct contact with the evaporating coil.

Unfortunately, leaking refrigerant may indicate another problem to be repaired which is not properly addressed by merely recharging the refrigerant level back to factory levels. The proper thing to do is:

1. Test for the leak and attempt to repair it.
2. If the leak is slow or not immediately detectable, an injection of dye with the refrigerant can be used to reveal the leak.
3. The leak may also be addressed by injecting a sealant along with the refrigerant which can eliminate small leaks.

Leaks typically occur at fittings and connections but sometimes occur as pin-hole leaks in the evaporating coil or the condenser coil. The only adequate repair for leaks in these coils is replacement.

Compressor Not Operating

The air conditioning or heat pump compressor is not working. This may mean that one of three of the following circumstances have occurred;

1. The compressor has reached a high temperature due to working so hard to compress and circulate the refrigerant gas that it is too hot and shut down, a condition known as thermal lockout. This condition, the accompanying diagnostic code, and status message may be displayed on your thermostat. This condition can also result in a tripped breaker.
2. A capacitor or the contactor switch controlling the compressor has failed so the compressor cannot be started or run properly.
3. The compressor may indeed be a failed or bad compressor that needs to be replaced.