Temperature overshoot - Forced Air AC, Gen 3

[ajsdave]

Six weeks ago I replaced my Gen 1 thermostat with the latest model.  It routinely overshoots the setpoint, e.g. set point is 79 but the AC runs until the temperature reaches 76.  To me, that is a significant error.    I have a traditional condenser/evaporator forced air unit (in good working order).

I've read the other "overshoot" posts, but do not see anything that addresses the problem.  If the thermostat is "learning" I would have expected it to have been dialed in by now. 

Tech info:

Base Software 2.3.51/3.1, Model backplate 5.26

Software 6.2-27, Display 3.7

Auto-schedule

Auto-Tune

Please advise.  Thanks

[CoolingWizard]

@ajsdave , what your are experiencing is sometimes called the “temperature glide”.  Your HVAC system is clearly very efficient. What should be happening is the as the set point is reached, the nest deactivates the compressor and leaves the fan on. However, this seldom glides 3-degrees.  Next time this happens, can you note if the compressor turns off as the set point is reached or the compressor stay on. 

AC Cooling Wizard. 

[ajsdave]

Thanks, Definitely not the "glide" full compressor running for at least 30 minutes past target temp on Nest schedule.

[CoolingWizard]

@ajsdave , by chance, in your thermostat settings, do you have Airwave On or Off?

AC Cooling Wizard

[ajsdave]

Airwave is set to "ON".  It seems to me that the thermostat is ignoring the temperature settings in the schedule and reverting to cool to 76 degrees for some reason.  In the schedule, the lowest temp setting is 78.  thanks