Gas Furnace Furnace Blowing Cold Air

One of the most common causes of a furnace blowing cold air is not actually a repair at all.

Gas furnace furnace blowing cold air. Once airflow to the furnace is no longer blocked your furnace will be less likely to overheat and should function normally. The solution is to replace your dirty air filter with a clean one. 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.

This hot then cold air sequence happens over and over and your home isn t warming up. So what causes the furnace to overheat. If you notice your furnace only blows cold air on occasion but your home is still maintaining its temperature than this may be simply a setting on your thermostat. Change the air filter and see if your furnace starts only blowing warm air.

Have an expert inspect your ducts along with the furnace. Auto ensures that the blower will run only when the furnace heats the air. The blower keeps blowing to cool the furnace down to a safe level. The dirty air filter will block airflow causing the furnace to run longer to heat your home until it overheats.

Your furnace blowing cold air could be caused by hot air escaping through holes in the duct work that carries the heat throughout your building. Most commonly a dirty furnace air filter. The fan setting on your thermostat has two options on and auto. Your furnace may be blowing cold air because the filter is too dirty.

If your furnace is overheating that means your heat exchanger is getting too hot.