AC not blowing very cold, but not freezing.


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Old 09-01-12, 06:20 PM
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AC not blowing very cold, but not freezing.

Hey guys, having a bit of a problem with my central ac unit. Thought id get help here. Lately, the ac has been having to work harder to keep the house cool. Today, it couldn't keep it up, the outside temp was 90, the thermostat was set at 76, but the house was 80. I went to check the outside condensor, all seems fine, the compressor is running as is the fan, but the fat line is not very cold, it is sweaty but not very cold at all. The vents blow cool but not as cool as they used to. The small line is not hot like it is supposed to be, its just room tempurature, and the air blowing out of the condenser is not very hot either, just kind of warm.


I was thinking freon leak, but nothing is frozen up. Not sure if the compressor is going bad, not sure how to diagnose that, but I do hear it click on and hum and start to sweat.

What do you guys think??

Thanks.
 
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Old 09-01-12, 07:24 PM
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Hey guys, having a bit of a problem with my central ac unit. Thought id get help here. Lately, the ac has been having to work harder to keep the house cool. Today, it couldn't keep it up, the outside temp was 90, the thermostat was set at 76, but the house was 80.
I went to check the outside condenser, all seems fine, the compressor is running as is the fan, but the fat line is not very cold, it is sweaty but not very cold at all.
The vents blow cool but not as cool as they used to. The small line is not hot like it is supposed to be, its just room temperature, and the air blowing out of the condenser is not very hot either, just kind of warm.

I was thinking freon leak, but nothing is frozen up. Not sure if the compressor is going bad, not sure how to diagnose that, but I do hear it click on and hum and start to sweat.
What do you guys think? Thanks.
It is up to you; we can determine a lot if U can take a few temperatures & % level of indoor humidity.

All U need is a good thermometer (digital reading in tenths preferable) & and indoor Humidity Gauge

1) Helpful; Tonnage & SEER of Unit &/or outdoor condenser model number: Minimum SEER upped to 10-SEER in 1987

2) TXV or, orifice metering device? _______. Only if U know…

3) Outdoor condenser’s discharge-air-temperature ______-F
Subtract Outdoor air temperature: _______
Outdoor Condenser Air-Temp-Split _______

4) Need the ‘Indoor’ percent of relative humidity - in the middle of the rooms or, at Return-Air inlet grilles ___

5) Indoor Return-Air Temperature ______
Subtract Indoor Supply-Air Temperature ______ -F
Indoor temperature-split _______-F

If U can find a turn in the small liquid line insulate the temperature-probe; get its temperature for the subcooling analysis; tubing sensors are best:
Small liquid line temperature ____F

To measure return air the wet bulb temp, wrap a small/thin, wet (not dripping) piece of cloth around the probe and put it into the Return Air grille & then close to the closest Supply Air diffuser near the air handler (need air movement). Wait until the temperature stabilizes - may take a little while.

Return Air wet bulb ____F
Supply Air Wet Bulb ____F

Need the above information for troubleshooting - performance analysis.

Example below:
A Goodman 2-Ton 13-SEER condenser, @800-cfm indoor airflow; 80-F indoor dry bulb & 50% relative humidity; Indoor temp-split 18 to 19-F.
@ 85-F outdoors; 103.9-F - 85-F outdoors or around an 18.9-F temp-split;
@Indoor 75-F, 63-wet bulb around 50% RH - condenser temp-split is only 14.9F.
================
Summertime all electric farm home; (‘two’) Half-Ton window A/Cs, one upstairs, one downstairs &, one large dehumidifier in basement…Record High June Temperatures:
June 30, 2012; MY Meter; 62610 – 62140= used 470-KWh * .0985= $46.30
 
 

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