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06-08-2008, 07:57 PM #1
1st time running new Trane XL15i AC
I ran a little test today to better understand the capabilities of my new AC. Here is the data from monitoring a new Trane AC, 4-Ton paired to XV95 furnace -100k btu, T803 Tstat, 2800 sq. ft home, 30yrs old, 2 story.
I would appreciate any feedback comments on the numbers. Not sure if they are typical or if I have an issue.
I compared 1st floor (where tstat is) to 2 locations upstairs. Floor-1 is 1st floor, Floor-2F is front bedroom and floor-2B is back bedroom. I also included outside temp and humidity in the shade. Data in table below is Temp/Humidity%. AC had been off all night and I started it 9:45 this morning and recorded the initial values below. I set the Tstat to 65 to see if it could cool that low. My starting values are the initial numbers below.
........ floor-1 Floor-2F Floor-2B 0utside
initial 75/54% 80/49% 80/44% 87/62%
1 hour 74/48% 81/41% 78/40% 91/55%
3 hours 72/44% 81/34% 78/36% 96/45%
5 hours 72/43% 82/32% 77/35% 98/38%
8 hours 72/44% 83/29% 78/35% 96/40%
Additional info: The Tstat is set for 3 cycles per hour.
A couple of observations: The temp never went below 72 but the 1st floor felt cold compared to the upstairs and frigid compared to outside.
The upstairs front bedroom temperature never dropped at all although the humidity did and comofort increased.
Also my plenum was sweating........ as well as the 1st 2 feet of each rectangular duct that is conected to the plenum. Is that normal?
Considering it was 98F outside and 72F on the 1st floor I was not disapointed at all (although I had no idea what to expect). I am a little concerned about the 2nd floor temperature not changing much if any.
Thanks as always for the feedback.
If the data apears difficult to read it basically indicates that the downstairs temperature started at 75 and 8 hours later was at 72 but the humidity had dropped from 54 to 44%.
It also indicates that the temperature in the front upstairs bed room never dropped over the 8 hour period but the humidity plummeted from 49% to 29%.
Finally, the outside temp went from 87 to 98 during the test.
06-09-2008, 08:30 AM #2
My plenum above the coil sweats when AC is running.
Is this normal?
06-09-2008, 08:57 AM #3
If its not insulated its normal.
Either you have a bad thermometer in the floor2F, or its low on air flow.
06-09-2008, 01:15 PM #4
06-09-2008, 01:29 PM #5
Yep. increasing overall air flow will also increase it to the areas that already cool ok. So balancing has to be done/attempted before thinking about increasing blower speed/CFM.
06-09-2008, 03:21 PM #6
06-09-2008, 03:46 PM #7
Its an option. But it can have draw backs. It could raise your humidity by 3 to 5%.
Its used a lot, and each house is effected differently by doing ti. Try it and see how your humidity is effected.
The 803 can do cool to dehumidify, so if you set it to over cool, it may work out fine for you.
06-09-2008, 05:18 PM #8Regular Guest
- Join Date
- Feb 2008
- Dallas & Longview, TX
I'd also add to let the system run all night at a comfortable set point. The room/furniture etc. hold alot of heat and upstairs on a 100* day is tough to overcome especialy if room 2F has alot higher heat load. It may circulate enough cool overnight to cool 2F more but a single unit on a 2 story may take some tweaking even from the best of techs.