I have a Honeywell thermostat RTH230B and this issue just came up today with the air conditioning not shutting off after it has reached my desired setting. The a/c continues to run and will never shut off, I have tried to delete all programs, I just want it to keep my desired temp plus or minus 2 degrees as I have it set... any ideas?? I can shut if off manually but its not automatic as it always has been before, example it was set at 86 degrees for vacation, I came back set it to 78 degrees and when I woke up it was 72 and still pumping cold air. Thanks for you help

Try taking out the batteries and putting new ones in. that should erase the old settings