I have a Coleman Evcon DGATO56BDD furnace. Several times a day the blower motor turns on when there is no call for heat. When this occurs it blows cold air for several minutes and then turns off. Also when this happens, it is at the same times each day (ie. 2:15pm, 8:15pm, 4:15am). I replaced the thermostat and checked for error codes. The furnace is indicating no error codes.

Sometimes the exchangers have a heat soak. This is when the fan off temp is set too low and after going off, the heat builds up to start the fan again. I have also seen this in attic furnaces when ambient temps are high and you have an older pilot flame.

My coleman model BGU07512RX runs then once its up to temperature then nothing but cold air comes out and the green light is flashing 3 times what does it need