We have a two story home. The big AC unit from the first floor is not cooling. Home is going to be 3 yr old. We start noticing that when we set it to 75 it could only keep the house at 80, and that's because the second unit upstairs has to keep with the cooling of all the house. Symptoms: outside air coming out from the big unit is not warm like the other. Small copper pipe it's cold all the way to the attic. So a lot of condensation in this small pipe. No other water around and filters are HEPA installed in march 2009. Air flow also coming to slow and not cold. Unit keeps working all day, that I had turn on the fan only. What should I do to fix it? Is it a freon leak? Thanks for your help in advance.

Sounds like the indoor coil may be froze up, shut the system down, switch the fan switch to "ON" on the thermostat. Let the blower run for a couple of hours. Do you notice any ice build up inside near the coil?

Yes, there was some ice build-up. What can I do? Thanks

Get it thawed out by just running the fan for a couple of hours with the air conditioning off. Once its thawed check the filter, normally a coil freezes due to lack of airflow or low refrigerant.

Thanks, I went and bought new filters while AC was off with the fan mode only running as you suggested. After new filters installed air flow improved, however once the AC unit has been set up to 72, for the last 45 min AC is still at 78. I guess it is a leak? Coils are unfrozen now with only some condensation, but still copper coil still is cold. Thanks!

Depending on the humidity it may take a little longer than 45 minutes to start dropping the tempature. The system may need to be looked over if after some time it doesn't gain on the tempature. You may also call in a pro just to check things over, check the refrigerant and make sure everything is up to par.

Called the specialist and after 72 dollars later they found a leak in the evaporator coil. They had to used a device to detect the freon. Since it is inside the evaporator coil system they will have to replace it with a new unit. In the meantime they add 1 lb of freon, since it is a small leak and to keep the house cold. Thanks for all the help provided.

No problem at all! Just curious,how old is the system?

It is going to be 3 years. Trane. But that part (evaporator coil system) was changed in January 09 under warranty, since we had another issue(little paper particles flying away all over the house). Now since it is a unit with defect, they will give us another one to fix it. Company is Big Tex.

Trane as well as a few other manufactures are having evaporator coil problems and naturally most of these problems show up after the first year of operation. Some of the coils have been modified to correct the situation. Hopefully you will get a good coil this time around. I believe Carrier might have the most problems with the N coil design and that is a real piece of work and a coil to avoid if possible.