A/C Doesnt Cool more than 20 Degrees?


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Old 08-04-11, 08:06 AM
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A/C Doesnt Cool more than 20 Degrees?

Had a tech tell me that my unit is unable to cool my house more than 20 degrees less than outside temperature... He put a thermometer in the vent, and showed me the air temp coming out of vent was 80 degrees, its 100 degrees outside.

Is this correct? I dont remember it being this dang hot in my house in the past. He said Freon was good, everything was ok. Could something else have changed to be causing my house to be so hot? Something in the programming, or the Thermostat? Leak in the Duct in the Attic?

Its been been getting up to 108 here in Texas...inside of house is almost 90 degrees.

Thanks for any and all help.
 
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Old 08-04-11, 08:32 AM
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I think it's BS unless you unit is extremely undersized. If it kept it cool when the outside temps were the same in the past...then it should now. If you aren't getting at least a 15 degree difference (18 is better) between the return air temp (basically inside house temp) and air at the vents....there is an issue. Put your hand on the lines of the outside unit.....one should be warm...almost hot and the other should be quite cold. If they aren't..call another tech.

I can cool my house to 70 or lower if I really wanted to...and that's when it's 105 and higher outside.
 
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Old 08-04-11, 08:35 AM
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Oh....did he open up the area where the cooling coil and fan are housed inside the house? Did he check for a clean coil? Did he check your filter?

All of this is assuming you have a split unit. One unit outside with a fan and compressor and another unit in the attic or a utility closet that has the cold coil and air handler fan.

If you have a package unit (everything in one big box on the roof or outside on the ground) then you won't be able to check much very easily.
 
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Old 08-04-11, 07:55 PM
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two questions. do you have a thermometer? and can you gain access to your indoor coil? if you answer yes to both, good. take a temp reading of the air coming out of the registers as well as the temp of your return air. you should have almost a 20 degree difference. now take a temp of your indoor coil (also make sure its clean) your coil temp should be almost 40 degrees colder than your return air. say it 90 inside the house, your supply air should be around 70 and your coil temp should be around 50. you can also check the outdoor unit. take a temp reading of the air outside and take a temp reading of the air blowing out of the top. you should have around 30 degree difference. so if its 100 outside, the air blowing from the top should be around 130. these are a couple easy ways for homeowners to check if there unit is operating near what it should be.
 
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Old 08-11-11, 08:08 AM
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Okay here is some info. Checked this in the evening, so it was a little cooler in the house.

Outside unit is: CLJ36-1A
Inside unit is: A-43-15

Temp outside close by the condenser: 103.5
Temp 1st floor: 82
Temp 2nd floor: n/a
Temp on the return: 78
Temp just after Evap coil: (inside the duct) (didnt measure)
Temp on the supply register close to evap coil: 57
Temp on the supply register far away the evap coil: 57.9

Looks like the unit is doing its job? Really thinking the issue is the area above converted garage needing more insulation, and air leaking out of the attic stairway door.
 
 

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