I'm poor at making long stories short, but ...
I had the Carrier Infinity system installed at my new house (including 24ANA a/c and 58MVC furnace).
During the winter, I noticed that the temperature readings were incorrect -- high -- due to sun exposure on the a/c condenser, where the outdoor air thermistor is located.
Because of my lot, and the size of the a/c, there was no shaded location available.
The system uses outdoor temp data for THREE things:
- Display "outdoor temperature" on the thermostat
- Determine the difference between outdoor air temp and outdoor coil temp
- Determine whether, and how much, to roll back indoor relative humidity to prevent condensation
Bad information ... because of sun ... was likely to screw up at least the first two. My HVAC guys said I had to live with it.
Regional Tech Support, similarly, told me to live with it.
Repeated nagging calls and e-mails, however, to Carrier corporate, yielded the following information:
Allegedly, this auxiliary air temp sensor is ALSO the source of the humidity rollback trigger.Originally Posted by Carrier
The auxiliary sensor was installed today -- in a location selected by Carrier's instructions (north side, up high, covered, etc., etc).
The first problem is solved: the outdoor temp display is accurate. I may test the second function (by freezing the display and watching the RH setting, at the panel) or ... wait until winter.
I presume the third function (OAT vs. OCT temps) is fine, using the sun-enhanced temp.
I can't tell you how many hours and phone calls I had into this. The HVAC contractor finally told me that Carrier wasn't going to "re-engineer the system just for me."
So ... to those considering the system, owning the system, selling/installing the system: you may want to throw in the aux temp sensor for ANY install where the condenser MIGHT receive sun ... at any time of year.
It was a REALLY cheap/easy fix to a REALLY silly problem ... that shouldn't have taken ME so much time and trouble to resolve.
Hope it helps ... somebody