I installed a new thermostat about 6 months ago before winter. Everything worked well until I tried to turn the central air on a few days ago. The compressor outside turned on, and the blower turned on, and blew cold air for a few minutes. I went back and checked it and it was blowing hot air. I went into the basement to check and the furnace was lit. I checked all the wires and called Honeywell customer service. They said they problem was with the furnace. The furnace is only about 2 years old, and the central air about 3 years old. I only have 4 wires coming out, I don't know what could be wrong. Thanks

Check fuses and circuit breakers for the outside unit. If it ran for a few minutes and quit now it might have tripped the circuit or blew one of the fuses outside.