A few days ago I had my HVAC replaced with a new Trane variable speed system (TUH2B080A9V3VAC gas furnace + XL15i 2.5 ton air conditioner). Although the system is cooling just fine - in fact much better than the old system, which would run all the time and never reach its target - I'm generally an informed consumer and knew in advance about having to configure the furnace blower to the size of the air conditioner, and when I asked during installation was infomed that everything was set up fine.
Well, today I decided to check and... everything's pretty much still at default. Considering I had to prompt them to hook up W2 to my two-stage thermostat, I should have known. (Note that I don't blame them, because I'm sure they aren't installing a ton of these VS furnaces - at least I hope not!)
* CFM set up for 3.5 ton outdoor unit (I have 2.5 ton + 3.0 ton coil)
* Set up for normal airflow
* Set up for 100%/1.5 minute delay (not Comfort-R)
* No Y-O jumper for Comfort-R
* Set up for medium-low heat (odd that they would change this from "normal")
Now, after living with the system for a few days, it's cooling the house plenty, but it may be doing too good of a job - even on a hot day yesterday, it didn't run between 2AM and 11AM, and by then it was getting a little humid upstairs and someone actually turned down the thermostat.
Due to my large, spread-out bungalow with only one HVAC system, I've always had the fan on at 100%, and am finding that the 50% normal operation of the Trane may not be keeping the air from stratifying. My concern is, because the 50% airflow is already so low, by the time I "right size" the CFM to the tonnage, it's going to be even lower.
So, some questions:
1) Would you configure this for 3.0 ton or 2.5 ton?
2) I'm planning on wiring for 80% continuous fan (I have the instructions). Since this involves adding a jumper to O, would I want to enable the Comfort-R dip switch or not? I realize there won't be fan ramping, but should it still be done?
3) Should I leave heat on "medium-low" or go back to "normal"?
Thanks for your assistance!