On Tuesday, August 15, 2017 at 10:56:20 AM UTC-5, JR wrote:
We have a new Carrier furnace/AC & Touch & Go thermostat.

1) The AC keeps running past the setpoint but only shows the setpoint as Actual temp. Set=73 Actual=73 but real temp is 71. 1st repairman said it was normal to run 3 hours for 1 degree & be 2 degrees colder than setpoint & this is how new ac works. Told him I set U2 backlight to OFF & U4 program to NP. Still told me nothing wrong. 2nd repairman replaced thermostat & it worked. That was until I set the Advanced Settings U2 backlight to OFF, that makes the AC run on. So I turned the U2 backlight back to ON & now it stops at set temp. Why is the backlight controlling the AC shutoff? Hoping someone can figure this out before I call for the 3rd time because we are stuck with the backlight on.

2) The Actual Temp drops 1 degree when you go to start the AC. Actual=74 & I Set=73, then Actual drops to 73 immediately & doesn't click on. You then have to go to 72 to hear the click on & reset to 73. So now I click down 2 degrees to 72 to hear the click & bump up 1 degree back to 73.

Anyone have this problem?


Ask you HVAC installer if he/she/it installed a gasket behind your thermostat to keep air from inside the wall from getting into your thermostat. Sometime the hole in the wall for the thermostat wire can allow air from the wall to throw off the thermostat. If it's an interior wall, it may not be insulated and there can be quite a bit of air flowing out the wiring hole. ヽ(ヅ)ノ

[8~{} Uncle AC Monster