Take a thermometer and check the discharge air temp off the condenser
outside. Then subtract the outdoor temp from it.
What is the temp split?
You way be drawing hot air from the attic or have duct air leaks.
The system could be overcharged.
http://www.udarrell.com/aircondition...e-airflow.html

There is somewhat of a condenser Temp/split guide on my linked page.
http://www.udarrell.com/ac-trouble-shooting-chart.html
Check out the other pages for more information.
Can not tell from here. - udarrell - Darrell
--
Engineering Air-Conditioning for "Human Comfort Zone Goals"
NOT merely the highest SEER Goal
http://www.udarrell.com/air-conditio...tent-heat.html

===========
"John" wrote in message
...
Hello group..
We have a new house with a Carrier Infinity HVAC system and I need to run
some things by someone(s) who are familiar with it. The outside unit is
the
38TDB condenser unit, and the VS8000 variable speed furnace with the
infinity control thermostat.
We moved into the house in late November so didn't really use the AC much.
The last few days were unseasonably hot for this time of year here in
central Texas (90-94 degrees) and last Sunday I set the unit to 75 degrees
(house was maintaining 77 prior to the adjustment) The unit switched up
to
high speed and ran and ran for most of the day and never was able to
satisfy
the 75 degree setting. Once it reached 75, the unit kept switching back
and
forth between high and low speeds (both compressor and fan) but couldn't
satisfy the setting of 75 degrees. I have noticed it doing the same thing
yesterday, when we got home it was running on high and the house was 76
but
the unit was not able to satisfy the swing to bring the house below 76.
Again, it kept switching between high and low. I checked the filter
monitor
which this unit measures pressure so figured it should be pretty accurate,
and it showed 71% used. I went upstairs and checked the filter, it did
show
dirt but easily shows light thru the filter. I went ahead and put in the
new one (original from November, but these are supposed to last 6+ months
and the installer told me the unit will tell me when to change it)
Also, Carrier brags about how quiet the compressor units are, but when
this
unit starts, it's VERY loud(buzzing from the compressor), and quiets down
as
the pressure increases..Is that normal? I had a Lennox that was much
quieter...
I am not looking for advice to fix the unit myself, but trying to find
input
from people who have these units or install/service them, to see if what I
am experiencing is normal, or if I should call out the company that
installed it..I don't want to call them if the unit seems to be working
normally..I know this system doesn't operate like a standard unit.
I know it's supposed to be a really good system, but not ever having one I
don't know if I should worry or call the contractor..The house has the
best
insulation we could get, has tech shield decking and low E windows so the
unit should have no problem cooling the house if they sized it right..The
house is about 1625 sq foot one story..I can't remember if it's a three
ton
or a four ton. I know you can't tell without a manual J if it's correct
or
not but here are the numbers:

Condenser part#38TDB048300
Furnace#58CVA110-20


Thanks alot for any recommendations...

John