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walters_12 08-04-2011 11:27 AM

A/C blows warm air
Hi All,

A couple of nights ago we noticed our A/C was running all night, but not cooling our house. We have strong air flow through the ducts (blower works), but the air is warm. Also, no water is draining out of the condensate drain line. And, the outside compressor fan runs fine (not sure about the air compressor, though).

I replaced the air filter this morning, turned the A/C off, and have been running the fan--thinking it the evaporator coils might be frozen.

With this information in mind, I have three questions:

First, was I incorrect to assume frozen evaporator coils because no water was draining?

Second, how long do I need to run the fan to defrost before I should try the A/C again to see if that is actually the issue? I mean, I don't want to restart too early.

Third, aside from the sound, is there any way I can tell if the air compressor in the outside unit is working properly?

Thanks for the insight!

gregzoll 08-04-2011 11:55 AM

If the outside unit is doing its job, you will hear a humming/whooshing sound of the refrigerant going through the larger of the lines on the line set, and it should feel as ice cold where the large line enters the outside unit.

Temp outside close by the condenser:
Temp 1st floor:
Temp 2nd floor:
Temp on the return:
Temp just after Evap coil: (inside the duct)
Temp on the supply register close to evap coil:
Temp on the supply register far away the evap coil:

walters_12 08-04-2011 02:06 PM

Thanks for the reply gregzoll.

I'm assuming you want me to report the temperatures you requested. I have no way of testing some of these on my own. I can tell you that currently it is about 80F outside and that it is probably a little warmer in the house. It was 82F when I left for work this morning--rain chances kept me from opening windows.

I'm heading home in about an hour to check the unit out, see if it has defrosted, and see if the condenser will turn on. Basically, need to know so I can call a tech before the end of the business day.

gregzoll 08-04-2011 02:37 PM

If you can get a kitchen thermometer that goes from 0 to 220, it can help measure those temps. I use something like this You may have to open up the panel at the a-coil to see if it is freezing up. You can also check to see if the larger line is getting cold, by placing your hand on the lineset where it enters the outside unit.

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