Why is the furnace blowing cold air?
Why is the furnace blowing cold air? Your furnace may be blowing cold air because the filter is too dirty. A dirty air filter blocks airflow over the furnace's heat exchanger, causing it to overheat. When overheating, your furnace can trip a high limit switch, causing the furnace burners to shut off so that the heat exchanger does not crack. Does furnace fan bring fresh air? This fan is wired to your furnace fan, so when the switch is turned on, it activates your furnace to circulate air which then brings fresh air into your home through your fresh air...