I have a new Infinity system installed, and it's running great. There is an issue with the Infinity Control that requires AC Airflow set to Maximum as a workaround; until that's fixed the system won't be doing the Comfort reduced airflows in cooling. Also, the system has not been balanced yet, but there's not much balancing that can be done other than adjusting how far room dampers are open.
Furnace - 58MVB080-20
Condenser - 25HNA648A300
Evap coil - CNPVP6024ATAAAAA
This is a heavy masonry and plaster house, not tight construction, high thermal mass. No direct sun on the thermostat.
Manual J heat loss for the house is approx. 26k sensible, 4k latent at 95 OAT/72 IAT. I keep the system set on 73 degrees, 46% humidity. The published design temp for my location is 92 according to the county; there are more than a few days a year that exceed that temperature.
The Infinity condenser is a 4-ton unit. Even after derating the unit for 73 degree indoor return air - which is being overly pessimistic, since the return air should be a few degrees warmer than that - it's still slightly "oversized". But it's acting "right sized", struggling to keep up when outdoor temperatures go over design.
The weird thing to me is what temperature I feel comfortable at, and how it changes during the day.
Morning - AC does not run. Comfortable at 73.
Afternoon - AC turns on High and stays there, even if it's only in the 80s outside. Might need to bump the thermostat down to 72 to be comfortable, otherwise it seems to take too long to start running the AC after the house starts to heat up. Indoor humidity 40% or less, even when it's muggy outdoors.
Evening - AC continues to run, usually on High, eventually staging down to Low, up to High, down to Low, as would be expected at less than full load. 73 starts to feel too chilly.
Night - AC runs late into the night, usually shuts off about midnight to 2 am and stays off for the rest of the night unless it comes on to dehumidify. 74 feels about right.
Is this normal? Should I just set the schedule to move the setpoint around and be done with it, or is this an indication of some other problem? It does seem weird, though I know that the Infinity Control doesn't behave like a traditional thermostat when it comes to system operation and runtimes.