# Bryant Evolution AC not responding to thermostat controls



## dvleemin (5 mo ago)

Hi All,
I have bit a weird problem with my Bryant Evolution AC unit. At a very high level it is not responding correctly based on the thermostat.

Here is specifically what is happening and what I have tried.
- Yesterday with the thermostat in cool mode, and the cooling temperature set below the current temperature for all three zones the AC unit neither the AC unit nor the fan turned on (as viewed in the status screen on the thermostat). However I noticed the actual AC unit itself running. 
- I turned the power off on the furnace, and the breaker for the AC Unit, let it sit for a few mins and then re-started everything. After everything re-booted, and it went through the system checks, the AC unit turned on, and in the status screen it showed the AC on, and the fan on. About 10 mins later, the status screen then showed the fan off and showed the AC unit off (temp was still below so should have stayed running). However, the AC unit itself kept running - even with the fan stopped.
- I then turned the thermostat to heat, and set the temp higher than one of the zones. The furnace and fan then kicked off normally, and it also showed the furnace and fan was running. I turned down the temp and everything stopped as expected. 
- With the thermostat in cool mode I manually turned on the fan to high and it turned on as expected.
- Then as I was writing this post, the thermostat displayed an error:
- First Error screen:
- No Sensor Data 
- Outside Temp: ---
- System Malfunction
-Second Error Screen
- Malfunction Alert
- Indoor Unit Communication Fault
- 12 events
- Zone 1-4 Comm Fault 
- 12 events

I went down to the furnace to see if the error code light was flashing, and it wasn't which I thought was odd. Then when I was down there the furnace fan turn on (when the error happened I had manually set it to High. The AC unit was running the entire time, and then just turned off again.

Any help would be appreciated.

Darryl

AC Unit Details:
Bryant Evolution 2 Stage AC
Model 187BNA060-A


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