Author Topic: A/C problems  (Read 2561 times)

Offline dcalthetiger

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A/C problems
« on: August 05, 2009, 09:47:10 PM »
I'm very disgusted with the excessive amount of water that is blowing out of my registers. I have a 5 ton Lennox heat pump that is 9 years old. I recently had the coils cleaned with acid. My return air filter size is 20x24. I was told that possibly my return air filter size was too small. I have hard duct throughout my system and i checked the insulation around each and it looked fine. I don't know where to turn but it looks awful on the sheetrock ceiling. Not to mention what the water is doing to my laminate floor. Would appreciate any help.

Offline Repair-man

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Re: A/C problems
« Reply #1 on: August 05, 2009, 10:10:43 PM »
Generally we use 1.5 sq ft per ton on the return air.

What is the square footage of the house?
« Last Edit: August 05, 2009, 10:16:19 PM by Repair-man »
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Offline dcalthetiger

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Re: A/C problems
« Reply #2 on: August 05, 2009, 10:18:38 PM »
2400sq ft

Offline Repair-man

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Re: A/C problems
« Reply #3 on: August 05, 2009, 10:23:03 PM »
So you are over-aired to begin with. Realistically you should have a 4 ton system.

 That, coupled with old, hard inefficient ducting and likely poor insulation in the attic will cause the registers to sweat. That also can include air leaks in the return air duct going to the air handler. It's a wonder your windows don't sweat too :)

Your best solution is to have another return air duct installed at the far end of the house. It can be tied into the existing plenum. Replacing the old supply duct with new flex-duct would do wonders  also. Not as difficult as it sounds.
« Last Edit: August 05, 2009, 10:25:42 PM by Repair-man »
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Offline dcalthetiger

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Re: A/C problems
« Reply #4 on: August 05, 2009, 10:46:45 PM »

The supply duct is only 9 years old. The existing blower sits in a closet with the filter on the bottom of the unit. If I remove that filter and put one in the door of the closet that has a cutout that is 20x30 already there. Do you think that would help? Also I have over 12 inches of Blown in fiberglass throughout the attic. Looks like that is sufficient. I live in the southern part of Louisiana and my electricity bill Just went over 100 dollars last month.

Offline Repair-man

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Re: A/C problems
« Reply #5 on: August 05, 2009, 10:53:54 PM »
An extra return air  grille and round 12" duct can be run from the attic down past the unit to the base, giving you better return air. Place the 12X12 grille in the master bedroom or relatively far from the existing unit. Again, you are over-cooling the house with all that tonnage so something needs to be balanced out.

Be sure you have opened ALL of the air vents in the house, even in rooms you may not use. Adding another duct run or two may take some of the static pressure off the current runs a bit. You could run another one in the den or kitchen to make up for the difference.

Great bill, by the way!  You are cooling the house so fast the darn thing doesn't have to run a lot. What Brand and SEER rating did you get?

Last question...was this 5-ton replacing a 4-ton previously?
« Last Edit: August 05, 2009, 11:15:19 PM by Repair-man »
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Offline JWWebster

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Re: A/C problems
« Reply #6 on: August 05, 2009, 11:08:02 PM »
Do you have a de-humidifier as well?
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Offline dcalthetiger

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Re: A/C problems
« Reply #7 on: August 06, 2009, 06:57:14 AM »
The brand is a Lennox I'm not sure but I think the seer rating is 15. It is the original unit that was installed in the house. The house is the same age. Also I do not have a humidifier.

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Re: A/C problems
« Reply #8 on: August 06, 2009, 07:03:39 AM »
Without seeing the actual duct system you have, I'd have to just say that keeping all the registers open is vital. It would not hurt to add a small return air as mentioned, but it may or may not stop the sweating in period of high humidity.
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