79 at return 64 at vent good???


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Old 06-22-06, 05:16 AM
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79 at return 64 at vent good???

I put my Walmart thermometer in front of the vent closest to the air handler and got 64 degrees. The air going into the return was 79 degrees. Outside was 87 with humidity.
Is this good on a 2 year old system? Should I be looking for closer to 60 degrees??
Many thanks.
 
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Old 06-22-06, 08:22 AM
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I think you'll find the pro's say 15-20 degree drop is average. Some systems will perform better than others.
 
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Old 06-22-06, 09:21 AM
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So I should have it looked at?

So my 'drop' is only 14 degrees. So I should call a reptuable tech out to see why the 'drop' is not another 4 degrees or so??
 
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Old 06-22-06, 04:46 PM
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There is a little more to it than that...

Are you satisfied with the A/C performance as it is? Does it keep your interior humidity down enough? Too much? Are there any indications that the unit is not performing as it should? Lines iced up? Is your fan blowing at excessive speed?

Since you are questioning it perhaps you should do a visual check of the entire system paying particular attention to the ducts in the attic.

Maybe nothing is wrong with it. Maybe there is.
 
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Old 06-22-06, 06:30 PM
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Take the temps at each side of unit! I bet you will find that it will be around 16!
 
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Old 06-23-06, 06:06 AM
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Just an afterthought, but do you have a clean filter in the system?
 
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Old 06-23-06, 11:40 AM
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Filters clean

Yes I just changed the filters. I think maybe I have been reading too many posts here. The system seems to work well. I just thought by checking the temps. that I could see if it was working at it's best.
Thanks.
 
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Old 06-23-06, 07:34 PM
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Return grille face and supply vent temp differential is not a great accurate tool, it is just a rule of thumb, there are several factors that can greatly affect the readings one being the accuracy of the instrument used to acheive the readings lol/ routing and insulation values (heat loss) of the ductwork/duct leakage/blower fan speed/coil cleanliness and of course refrigerant charge levels. To get accurate readings Delta T you should take the temp readings using a accurate temp probe just before and just after the actual evaporator coil itself after the normal inside operating air temp has been acheived and the unit has run contiuos for at least ten minutes to stabilize. This is usually accomplished by drilling access holes into the duct work and should be taken along with the airflow readings and other basic checks to determine the health of your unit. You are probably OK nothing to stress about. Just make sure your coils/blower fan and filter are clean, you can use the readings you took as a baseline if you check in say a month or so and notice a change it might be time to have a tech check the superheat/subcooling values and airflow CFMs to see if the charge level or fan speed needs adjustment.
 
 

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