Causes for Short Cycling AC

I have a 2000 sf home with a 4 ton Goodman installed. The unit is about 5 years old, straight AC, strip heat. This unit has never been what I hoped. The front of the house is considerably warmer than the interior and rear of the home. I cycles on every 10 minutes (or less) and runs for 8 minutes, then shuts off. I have had several AC men look at it, and have been told various reasons for the problem. I have heard the unit is too big, the unit is too small, the plenum is too small, the ducts are too small, there is not enough insulation in the attic, the thermostat is in the wrong place, the ducts are in the wrong place, you aren't making enough static pressure, etc...
I am no AC man, but it seems to me that these are all possiblilties - or guesses. I can't imagine that everything listed is wrong. What are some ways to limit the issues? How much insulation should the attic have? What is the rule of thumb for duct sizes, unit sizes, cycle times? I would just like to have a unit that works right and doesn't wear me out with worry...any suggestions?
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On 26 Jun 2008 22:49:36 GMT, kennethbodine_at_sbcglobal_dot snipped-for-privacy@foo.com (Kenneth Bodine) wrote:

Where? Nevada, Florida or Maine?

WHat had you hoped?

That's nice. Now, which *direction* is the front of the house? The sunny side by chance (south?)

So it runs for eight minutes, then is off for two, then comes back on? OK, seems fair to me.

Of all those comments, that one is the one that may be correct.

WHere are the ducts?

Is this a packaged system, or a added to existing heat system?

In Maine, for AC, not that much... Goes to location, location, location.

WOrry? WHat are you worried about?
Next time put some facts in:
Where you are. Outside temperature? Temp in the cooler areas/rooms? Temp in the warmer areas/rooms? How much insulation you have? What type (even brand and model) of unit you have? If duct location is suspect, where are the ducts?
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Kenneth Bodine had written this in response to http://www.thestuccocompany.com/construction/Re-Causes-for-Short-Cycling-AC-14520-.htm :
------------------------------------- PeterD wrote:

OK, based on some of the feedback, it sounds like I short-changed you on information. I live in North Central Texas. The temp outside is in the low 80's at night, and high 90's to low 100's during the day. The unit I have is a split system Goodman single stage 4 ton straight AC (NOT a heat pump), with strip heat. The house is a single story ranch home with mostly 8 ft ceilings. The house faces southeast, in the shape of a T, with the lower part of the T facing north. 5 years ago, the garage was converted to a living area, and there was a 480 sq ft addition put on, hence the change to the 4 ton Goodman. The AC man used the existing ducts, added new 2 10" supply lines for the addition - broken into 8's for the bdr, and a 6 for the restroom and utility area - this is the part facing north, and it is very comfortable - about 75 degrees. The converted garage, which faces south, has 2 8's for a 20 x 17 area, and feels a little more humid, but still around 76 degrees. The center part of the home is the coolest, generally at about 74 degrees. The temp in the eastern portion of the house is the part that stays the warmest. It is generally 78 or 79 degrees, and very stuffy. Both of the bdr's have two 5'0 x 5'0 windows, one facing south, one facing north, and two facing east (1 per bedroom). The ducts for all the old house are located right in the center of the room, 7 inch round ducts. They were initially only used for heat - no AC. When the house was switched to AC, there was only about 1200 sq ft, and a 2.5 ton heat pump was attached. The home was very comfortable then, even cold. When I added the space and went to a new unit, I had hoped the house would stay as comfortable with the new system, but this is not the case. As far as insulation is concerned, there is about 6 inches of cellulose insulation in the attic, and r-11 in the walls. The windows are single hung, but have an additional storm window mounted, with about 3 inches space between the two panes. You asked what I am worried about. The short cycling worries me. I am afraid that I will blow the compressor - as the unit is getting more noticably loud as the years have passed - very quiet when I first installed, and now loud enough to wake me at night or have someone ask me what that noise is when it first comes on. After it runs for a few minutes, it gets pretty quiet again. Based on this data, is it still the consensus that the ducts need to be relocated? I hope this is a little more informative!! Thanks for the info.
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Similar warm in front, cooler in rear of the house. Most noticably in heat of the day. House faces the south.
AC stagnant (end cycle to beginning of cycle) time varies with the exterior temperature. And, the length of time AC is actually on varies with external temps and entry/exit traffic into the home. Not consistent figures like yours.
Thermostat location is typical hallway adjacent to bedrooms.
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Dave

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On Jun 26, 5:49 pm, kennethbodine_at_sbcglobal_dot snipped-for-privacy@foo.com (Kenneth Bodine) wrote:

To simplly get it to cycle less adjust the anticipator for a larger swing, or get a thermostat that you can adjust. For a hot room you likely need more supply, but I think you need an inteligent tech, as they all should have sold you a thermostat.
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