honeywell air condition not working?

The fact that your A/C won't get below 77 degrees should have nothing to do with your Honeywell thermostat. Any thermostat is basically just a switch. Either it's on or it's off. You could set it to 30 and it wouldn't make the system "blow colder". The problem is your air conditioning system, not the thermostat. Have you check your return air filter lately? The system could be low on refrigerant due to a refrigerant leak. The evaporator coil could be dirty and in need of cleaning. There could be several things wrong, but we would just be guessing as to what the problem is. Have you had your system serviced in the recent past? If not, there's not much we can tell you other than to have the system serviced by a reputable air conditioning contractor.

The honeywell TH4000 is just the thermostat on the wall and not the air conditioning unit itself. How hot is it outside and how long has it been on? If it is 100 degrees outside then your unit may not be big enough cool it down more than 77. If you have an old unit then it may be time to replace or repair it. Call the repair man.

77 degrees is not to bad. We usually keep our thermostat set to about 78 in the summer.

Your A/C unit probably can't cope. But you've given us no information. What's the outside temperature? the A/C model? the room size? etc.

Setting the thermostat lower won't make it any cooler if your A/C can't cope. If it's not capable of cooling the inside air any lower than 77 degF in the present outside climate, then whether you set the thermostat to 50 or 76 makes no difference, the A/C compressor will be running all the time in both cases.

Honeywell Pro Th4000

It sounds like the unit and not the thermostat. If I where you I would consider a geothermal system. In the end it will save you a bundle and the tax credits are great.