I have upstairs Honeywell Thermostat showing me a square icon since yesterday. The upstairs AC is not working. It is blowing air since the fan is on but the air is not cold. I opened up the thermostat and replaced 3 AA batteries in it, but that did not make any difference. I have tried to find the manual on the Honeywell's website, but they don't have anything there. The picture of the icon is below.

  • 2
    what's the model number of your thermostat? you should see a plaque somewhere around the battery cover area, or at the back. – alt Sep 2 '13 at 23:15

We'd be able to know for sure with the correct model number, but assuming all Honeywell thermostats follow the same icon structure then this indicates that the Smart Response™ technology is off.

Honeywell CT8602 screen guide
Source: Honeywell CT8602 manual

According to this similar thermostat's manual, Smart Response™ this does the following:

  • Keeps you comfortable by automatically calculating exactly when the furnace or air conditioning should go on to have the house at the desired comfort temperature by the time you wake up or return home.
  • Saves the maximum amount of energy and money by automatically remembering to adjust the temperature when you leave home or go to sleep.
| improve this answer | |
  • The fact that the thermostat is currently set to hold 82* per the OP's photo is the probable reason SmartResponse is off; it's not needed if the temperature control program isn't in use. – KeithS Sep 3 '13 at 23:06

I agree with the comment and other answer; the model number would be very helpful.

First, the square, as JohnB found, indicates that the SmartResponse feature of the thermostat (which attempts to predict how far in advance to begin lowering the temperature in the home to meet the setting by the set time) has been disabled. Most likely, this is a natural consequence of your having the system set to hold a specific temperature all the time. In that configuration, SmartResponse wouldn't be needed anyway as there's no temperature change to predict.

Next, the fan running all the time is not necessarily a failure. Most programmables I've seen of this basic type have a switch that allows you to set the running mode of the blower to either "Auto" (Runs only when the system is actively heating or cooling) or "On" (runs 24/7 even if the system's not heating/cooling the air passing through it). By doing this, you keep the air circulating through the house, which if you have a reasonably well-designed system will help keep the same temperature throughout the house.

The actual temperature setting is more personal preference than anything, but 82* is hot. I'm in Texas, it's triple digits outside, and when I walk into my house I want the sweat to freeze. Well, not exactly, but between an office job and a pregnant wife we try to keep the home thermostat between 72-74*. At your 82* setting, depending on the temperature outside (and how efficient your home is) the system may never need to actively cool the air, because the thermostat (usually located centrally if at all possible, and out of direct sunlight) never reads over 82*. Try setting it to 72* or thereabouts and see if that doesn't kick the Freon coil into gear.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.